Technopeasant I find the combat in Eclipse at bit too airy, but Xonotic has a decent UT04 vibe.
I think Red-Eclipse-1 is the closer to UT actually, but it have it's own feeling, because of their very special movement mechanics (which is pretty good I have to say!)
Nexuiz just feels like a mess to me.
As for what I'm playing... depends. Unvanquished, wesnoth, morrowind, tales of maj eyal, RE1 (long time since last game, but I work in cycles)... mindustry could be nice, if not about the system freezes and many dumb choices (petrol almost useless except for plastanium, low level prog lang which is worst than all asms I can remember, etc) when digging in the game, but i still intend to finish the solo thing.
One game I have serious hopes for, is Thrive.