I'll openly admit it. I love the 3d rendered games. In fact, they're the only reason I dual-boot my PC. And, honestly, they're the real reason I defected to x86, in the first place.
My current favorites (in no particular order)
Papyrus NASCAR 2003
IL2-Sturmovik / Lost Missions
Unreal Tournament 2003 (if only I didn't have to run a crack on my legally purchased CD just to play it...)
As for the slightly older, budget shelf, iama- I really liked Alice. It's very trippy, if you have a machine with enough horsepower to crank the detail. (1+ghz / fast OpenGL card) I wanna play that game again, too. I loaned my copy to a friend and haven't seen it since. :-(
Of course, I also love the old games, too... But the power of modern machines opens up so many more possibilities for simulators. (My favorite genre, although I occasionally enjoy shooting stuff - I can't wait for Half Life 2.)