Suikoden 1 - My favourite game series, and the one RPG I've completed more than any other (I have 25 playthroughs now, if you include the two which I co-played with Paolo). Great cast of characters, and a story that's very loosely based on OUTLAWS OF THE MARSH/ALL MEN ARE BROTHERS/THE WATER MARGIN - a seriously amazing work and one of the GREAT CHINESE CLASSICS!!!
http://www.youtube.com/watch?v=u8N9_i1HgBg - Intro Video/Gameplay sample.
http://en.wikipedia.org/wiki/Suikoden - Wikipedia entry.
Suikoden 2 - Sequel and seems to be considered the best game in the series by people I've spoken to about it. I prefer the first, but that's largely due to TINTED NOSTALGIA GLASSES.
http://www.youtube.com/watch?v=_f4eGQ9MIWM - Intro video/Gameplay sample.
http://en.wikipedia.org/wiki/Suikoden_2 - Wikipedia entry.
Vandal Hearts - The first tactics RPG released on the PSX. It mixes a storyline that seems simple on the surface, but has levels of complexity when analysed, with cartoony graphics and ridiculous levels of blood. Fun game for sure.
http://www.youtube.com/watch?v=cU7XiTkMgRs - Gameplay sample.
http://en.wikipedia.org/wiki/Vandal_Hearts - Wikipedia entry.
Vandal Hearts 2 - A sequel. They changed the class system completely and went for a much more adult theme overall. Sometimes it can come across as preachy, but if you believe in like EQUALITY and UNIVERSAL SUFFRAGE and shit then you won't mind the lectures the characters give haha.
http://www.youtube.com/watch?v=2IjpA5-ftx8 - Gameplay sample.
http://en.wikipedia.org/wiki/Vandal_Hearts_2 - Wikipedia entry.
Breath of Fire 3 - Very traditional JRPG with some really nice extra features, such as the FAIRY VILLAGE and the dragon system. The graphics are still decent, the storyline is interesting, and the characters quite varied. Worth playing.
http://www.youtube.com/watch?v=pAPGcCyWeK4 - Gameplay sample.
http://en.wikipedia.org/wiki/Breath_of_fire_3 - Wikipedia entry.
Final Fantasy Tactics - In my opinion, the best tactics RPG that has ever been made. The storyline is a tiny bit hamfisted, but the music and job system provide entertainment you can lose yourself in for months. Plus there is a character named ZALBAG!!!
http://www.youtube.com/watch?v=tfPbKVvyWk4 - Gameplay sample.
http://en.wikipedia.org/wiki/Final_fantasy_tactics - Wikipedia entry.
Azure Dreams - Lighthearted tactics RPG which is focused on training monsters, adventuring into a tower and using the preceeds to fix up your hometown, and wooing a variety of women.
http://www.youtube.com/watch?v=Qh75Cq_Tmz4 - Gameplay sample.
http://en.wikipedia.org/wiki/Azure_Dreams - Wikipedia entry.
Saiyuki - Journey West : Tactics RPG based on MONKEY/JOURNEY TO THE WEST - One of the Great Chinese Classics! The humour is irreverent, Monkey is a total jerk (so accurate haha), the soundtrack and graphics are still great. Besides, none of this should matter anyway as you get to be MONKEY and PIGSY and shit! Hooray

!!! PS: MUSIC AMAZING!!!
http://www.youtube.com/watch?v=O96ztuDPPPE - Gameplay Sample/Trailer.
http://en.wikipedia.org/wiki/Saiyuki:_Journey_West - Wikipedia entry.
Blood Omen: Legacy of Kain - Very dark, 2D Zelda style game, with tons of interesting weapons and abilities, a really atmospheric setting, and a convoluted plot. HOORAY

! Plus BEING A SCARY VAMPIRES OH NO!
http://www.youtube.com/watch?v=P_11r1yE3FI - Let's play intro.
http://en.wikipedia.org/wiki/Blood_Omen]http://]http://en.wikipedia.org/wiki/Blood_Omen - Wikipedia entry.
Oddworld: Abe's Oddysey: Excellent puzzle platform game, great humour, dialogue system (hello, HELLO, follow me, OK!!!), and quirky plot. Even though you die thousands of times, it still keeps you playing.
http://www.youtube.com/watch?v=ckQSFcKMJ9k - Let's play intro.
http://en.wikipedia.org/wiki/Oddworld:_Abe%27s_Oddysee - Wikipedia entry.
I HOPE THIS WAS HELPFUL

!!!! I love all of these games to absolute bits, and I definitely recommend trying them all if you haven't already. Like seriously, all ten of these games have provided me with so much joy over the years. It was tough narrowing it down to just ten, and I was pretty RPG heavy here, but fuck, that's what I loved most about the Playstation really!