Yup, UT2004 is the best!
Doom3, well, to me, the single player is boring. The monsters are incredibly stupid, their AI is just script based. Example: You stand in front of a door, you open it and an Imp pounces on you... you open the next door... and an Imp pounces on you. You open another door... surprise, an Imp (which pounces on you, to be exact). Scary, eh? :lol:
And the multiplayer part, well, all you need is a fast computer, then you can play on a few maps with a few players. Not bad, but definitely not good.