I love UT2K4. Most are saying its one of the best games ever. I think it is from my game playing experience.. I'm no noob, my first PC game was Kings Quest 3 back in the day.
2004 has everything, great physics, great graphics (that look about as good as anything else on the market than perhaps FarCry but it runs on much less hardware), great performance, VOIP (voice chat), Voice CHANNELS (public, team and local for only your immediate vicinity), 100 maps are included out of the box, Assault and Onslaught mode (along with a bunch more, more typical styles), vehicles, a decent single player game with team management that kinda makes it a bit more fun, oh and voice recognition to control bots, not to mention some of the most efficient netcode and best bot AI in the industry.. only challenged by id softwares.
Yes I speak highly of this game.
Needless to say, I wont be buying another FPS game without all these features ever again. Its alot to ask for but I just cant enjoy a game anymore without VOIP/vehicles.. its going to be tough topping this game at all that it does.
I think Doom 3 will be the only other game I'll be buying in the near to far off future.. I hope it offers a decent SP experience and maybe something we dont know about in the MP game. We'll see.. but I'll be buying that one without hesitation as well.
I'm more of a fan of the "CounterStrike" gameplay (slower paced, less gay frag fests) but UT2K4 has enough and more for me to overcome that. As long as I stay out of the DeathMatch part of the game I find myself liking it enough to brand it my "favorite game of all time".