Vampire the Masquarade: Bloodlines
I think it deserves more attention than it gets. Game has amazing atmosphere, good story, great gameplay and realy interesting (and unique?) view about vampires. Game depicts them as shadowy figures, living their own lives, known only as fairy tales for humans. And I really liked that in game they aren't just some beasts, craving only for blood. They are more humane than most people, drinking blood only because they must, in order to survive.
Biggest letdown for me was weak gunplay mechanics. Most weapons just feel weak and their design is mediocre. Also you must download a buch of paches, because game is extremely buggy.
But despite these flaws I really enjoyed the game and I really recommend it for anyone who likes (fps)rpgs.