I'm not a big fan of FPS's but the FPS perspective of Fallout three is changing my mind on that. I would like them better if it was easier to aim where you want to shoot. Shooting with a mouse is a lot different than aiming a real gun.
Alien vs Predator 2 is a brilliant FPS. Having three completely, and I mean completely different characters with completely different levels and completely different tactics makes it well worth playing.