Joystiq - There's an RPG in my FPS!
From a few days back, Rowan Kaiser's regular RPG blog on Joystiq examines the marriage of RPG and FPS:
At the end of the 1990s, the superb Deus Ex managed to fuse both role-playing games and first-person shooters into a coherent whole. This wasn't an RPG with shooter bits, nor was it a shooter with RPG elements; it was both genres, in their totality, together at once. This
was a neat trick, and one that hasn't really been duplicated, not even by Deus Ex's sequels.
The crucial issue is this: first-person shooters reward player skill. The faster you are at aiming, the better you are at moving, the more likely you will succeed in an FPS. Role-playing games can involve that (especially action-RPGs), but they always rely on character skill. Your character statistics, items, and skills will help you succeed, or cause you to fail, regardless of how speedy you are with a mouse or a controller. Deus Ex managed to find just the right balance where both player and character skill were important for success.