Vampire: The Masquerade - BloodlinesScreen shots (Click to reveal)

Presenting Vampire: The Masquerade - Bloodlines, a visually stunning first-person role-playing adventure that combines intense first-person action with an open, non-linear world, rich character development and an immersive storyline. Built using Valve Source Technology - the same game engine technology used to power Half-Life 2, Vampire: The Masquerade - Bloodlines is based on White Wolf's pen-and-paper RPG series, and developed by renowned RPG developer - Troika Games. The game plunges players into the dark and gritty vampire underworld of modern day L.A. as a creature of the night, interacting with and battling mortals and other creatures of darkness with an incredible array of vampire powers, skills and traits. [Activision] Probably one of my favorite RPGs ever, and, considering it was the game that bankrupt Troika, I guess it didn't sell too well. At the time it was released it was buggy/laggy but the patches + fan patches seemed to have fixed that up (I played it... last summer I think... and it was basically bug/lag-free free)
Everything about the game was awesome, the weakest points of it were really the combat (they tried to do a bit too much with it) and that they couldn't use the source engine to its full effect. Along with HL2 it was the first game to use the source engine, and they didn't have the full documentation or something...
It has some pretty decent replay value too, playing as a Malkavian or a Nosferatsu changes the game up a lot. Malkavians have every dialog option changed (they are all insane) randomly hear voices (this scared the shit out of me at like 1 am) and have a bunch of other weird things happen (conversation with a stop sign awesome.) Nosferatsu can't be seen by humans so they have to move through the sewers to get places. Every class has at least one quest line to themselves if I recall correctly.
http://www.metacritic.com/games/platforms/pc/vampirethemasqueradebloodlineshttp://www.vampirebloodlines.com(Troika also made Arcanum: Of Steamworks & Magick Obscura and The Temple of Elemental Evil (both of which I think have been mentioned.))