What games would you recommend a second play through? Maybe not just a for it's secrets but a game you just got drawn into so much that you just ended up playing through it again. Explain why as well if you want.

Final Fantasy VII/IX - These are by far the best ones in the series for me. IX had such an awesome atmosphere and general feel to it that I could like NOT play through it again. Final Fantasy VII is my favorite game and I have played through it almost 10 times now, because to me it's just a great game to play and even now don't get bored to go through it again.

Chrono Trigger - Theres just something about this game that just draws you in. I don't know It's just a great game, overrated but still even today.. A game I can play again.

Halo Combat Evolved - Probably the most hyped games in history. There was just something about the original that really was fun and engaging that was kinda lost in it's sequels.. Halo 3 was alright though. Plus those big expansive maps were awesome to play through on Co-op.

Half Life 2/Portal - Best fucken FPS ever made so far. Can't fucken wait for the next one. The Cake is a lie GODDAMMIT!! Plus those talking machine guns are awesome.

Crackdown - This is pretty much Grand Theft Auto with super powers.. Too much fun. Story isn't the greatest but gameplay is too good that it doesn't even matter. Should check out Infamous if you liked this game as well. PS3 exclusive which is sad cause I only have an Elite.

Grand Theft Auto IV - One of or maybe even the best game Ive ever played. Everything in this game screams fucken awesome. The AI, Physics, Characters. Niko is the fucken man and the game just doesn't get boring.

I could replay Resident Evil 4 and Metal Gear Solid till the cows come home really. There's plenty to do and they never seem to get boring.

I couldn't pla a final fantasy through twice back to back. Not ever, much as i love them.

Jagged Alliance 2 is the one I come back to again and again. I must have played through it ten times plus by now. It's just basically the perfect tactical game to me.

I've finished basically every FF at least 3 times as well but that was more because I used to not have many games and played the ones I had a lot more!

I've played many, many games multiple times.  I haven't bought many games lately because I keep rediscovering old games that I still love.  Some of the most replayable games I know of are:

Metal Gear Solid 3: Snake Eater
This is one of the most impressive games I've ever played.  I just finished MGS4, which was absolutely fantastic, but it doesn't at all take away from the greatness of MGS3.  The graphics are gorgeous on the PS2, and the gameplay is deeper than just about anything else I've played on the system.  But watching the story over and over is worth it too.  The small amount of codec time was the best improvement to the series of all though.

Knights of the Old Republic
I've lost track of the number of times I've played this game.  I stopped counting at eight, and I've probably played it at least another six times.  I love being able to play as a completely different person every time.  Mass Effect is a superior game, but KOTOR will always have its place in my collection. 

Star Wars: Jedi Knight: Jedi Academy
The first time I played this, it was decent.  I liked being able to use a lightsaber in a realistic way, unlike every other Star Wars game before it.  Jedi Outcast came close, but it was still a little stiff (not that it isn't a great game).  The second time I played it, I put in the bloody dismemberment mod, and suddenly it became the greatest game of all time.  Hacking off body parts with a lightsaber while spewing blood all over the walls was my Star Wars fantasy come true.  It's a buggy mess of a game at times, but with the help of a massive amount of mods, it's seriously one of the coolest games I've ever played.

I've played every FF between 6 and 12 (except 11) a few times.  I played 7 more than any others, and even played it again recently just to see if I'd still like it (I did).  It's hard to get into Japanese RPGs for me now because American RPGs are just so much better.  I wish the Japanese games would drop the stupid hair crap and the pristine faces of every single character.  It's not cool anymore.

I'd recommend a 2nd playthrough of any game you thoroughly enjoy.

Sonic Adventure
It's fun the first time, and running through again at any point in time is just as fun. There's just something magical about SA1 on Dreamcast that will live on forever.

Kingdom Hearts II
The first playthrough was a little dull, I found. The Drive system didn't make much sense until about halfway through the game, when I figured out that by using the various drives, you could unlock special abilities (High Jump, Fly, etc), which is the missing feature from KH1 that initially pissed me off. The second playthrough is more entertaining, because you know what you're doing from the outset, and can just let loose. (Protip: There's a savepoint outside the battle arena in Hades (Olympic Colusium? I forget the name) that refills your drive meter to full.

Super Mario Sunshine
The game was interesting and fun enough the first playthrough to merit a second run, -cough-yearslater-cough-

Metal Gear Solid 3
YES.

I actually want to play through Final Fantasies 7, 8, and 9 again because it's been at least eight years since I played any of them.  That's what I would do, anyway.

Every Zelda game ever
I am such a huge douche because I've beaten almost every Zelda at least twice (the two exceptions being The Adventure of Link and The Minish Cap, which I actually ordered from Amazon a while ago but I got a defective copy, fuck fuck fuck (also the four swords games don't count)).  I've beaten Ocarina of Time at least ten times (probably more though).  Fuck.

Metal Gear Solid 3
I've beaten it like three times, maybe.  It's a new experience every time, really, because I'll either play on a different difficulty or discover something new that changes the experience.  Good times.

Prince of Persia: The Sands of Time
This is good times.

Super Mario Galaxy
Man I am such a faggot, I'm actually trying to get all 120 stars as Luigi so I can get that secret 121st STAR!!!! which I hear is bullshit and not really worth it but whatever this game is fun man.

edit: oh yeah and

Resident Evil 4
I beat this game like 3 times in a row I think. 

Half Life (And sequels) - The FPS that captured my imagination all those years ago and still remains the very root of everything that I find cool in games since. Headcrabs, I mean come on. Everyone loves headcrabs. Eaaarrrch *chomp*

Grand Theft Auto 3 - This is where the series stopped being a game and started being an action movie that you, the player stars in. Still the best GTA in my opinion, please don't chase me out of Wamging Village with pitchforks.

Fallout X - Any fallout game. There is never enough killing then stealing from the person you killed. That is one of the most satisfying things you can do in a videogame.

Metal Gear Solid - You know why I don't even have to justifty that one.

Red Alert 2 - This is, in my opinion - the best RTS game ever made. I have yet to play a strategy with such great balance in gameplay. The units are designed to perfection and it is isometric and not poo 3d. It has been stated here before in reference to Fallout but I don't see why they don't make more super-rendered isometric games instead of chewing up your PC with total 3d immersion. What about 2.5D with 2D backgrounds and hi-def entities? Surely that could achieve near photo-realism given the current technologies.

Final Fantasy VII - Because most people are too cool to say this is their fave FF.

Rollercoaster Tycoon - I may have grown out of this one a bit now but back in the day I played this time and again. My theme parks were all terrible financial black holes but the fun made up for that

Call of Duty 4 - This is the current height of the FPS genre. Yeah yeah, Killzone and Crysis have eye watering graphics but this is where the gameplay and graphics are met to my current standards. I have completed this on veteran.

MGS4 and GTA4 also have magnificent replay value but obviously I have not owned them long enough for them to have shown the test of time.

Half Life - Head humpers, 'nuff said!

Morrowind - I'm only on my 1st character, btu I know I definately will be playing it with more and more characters in the future. Goddamnit getting away with killing a slave rtader is fun *insert evil dance of Fireblade murder* mwahaha

Castlevania Series - Mostly the 'X of Sorrow' games, for me going through with different challenges is fun, especially seeing as I've found the easiest challeng so far for Dawn of Souls. Using KNUCKLE weapons only, I'm upto agune, I just need a little tiny bit of leveling first, and maybe a hellboar soul to upgrade my knuckle.

Ratchet + Clank series - I've played up until Gladiator, and I play through them over and over for the simple fact I can blow shit up using bigger and bigger weapons each time.

Now if only I had the cash for teh RY3NO ;_;

Super Mario Brothers 3!! Awesome!

i've played through deus ex dozens of times. i'm not exagerrating. the last couple of times i haven't found anything new so i think i've seen it all now but that game has so much great stuff hidden away. i love deus ex!

Super Mario Brothers 3!! Awesome!

This and...

Diablo 2
You are practically expected to play this game over and over and over again.  This game is one of the greatest games ever made.

This and...

Diablo 2
You are practically expected to play this game over and over and over again.  This game is one of the greatest games ever made.

I've got pretty far in Diablo 2 about 10 times but I've never finished it. Something always happens to stop me. My friend and me are playing through it LAN when we catch up though so I'm confident I'll eventually get to the end.

Jagged Alliance 2
I love this game it's so awesome, especially sniping from far away and getting on of the enemies in the head plus I'm currently playing the v1.13 mod I just discovered and it's even better.

Fallout/Fallout 2
I love stealing and planting bombs on a person and running away LOL it's so funny!

Chrono Trigger
The only RPG game that I ever play anymore, only from time to time I play it on my PSP.

Resident Evil 4
The best Resident Evil out so far, with unlockables it makes replaying it so much more satisfying.

Resident Evil 2
I love this the first time I played it and I still play it from time to time.

Resident Evil 3
One of the best in the series alongside RE2 and RE4.