I'll echo what the others have said.
AB3D runs very well on 030+ so it will fly on your 060. It's an awesomely good game and one of my favourites.
AB3D2 is a bit clunky on 060 and way too hard for me. I played through AB3D many times, but lost interest in AB3D2 very quickly.
Breathless is better, but the engine is a bit simple and rooms start to feel very samey after a while. Try it, YMMV.
Doom is very good on 060 and a classic game as well. You can use many (all?) of the expansion levels created for the PC version. Do yourself a favour and pick up a Doom collection on eBay or something.
I believe Genetic Species is highly recommended too, if you like the FPS genre.
Haven't played Testament.