New office PCs. WTF can we play on them?

We just got some new Dell office PCs. GX100s with Celery 800s, 128MB RAM and i810 video (ugh… I know), Windows 2000. We have these all on a LAN and I am wondering if anyone can guess what the OpenGL performance (or even D3D will be) good enough to play Quake 2 or Half Life and other “older” FPS and strategy games. Any ideas what we could run on these? The guys would be more interested in FPS than anything else, I think.

PS - The server machine is a P3-450, 128MB, NT4 with onboard Rage IIc graphics (double eeech). Bonus points given if the games you select can run on that too.

Half-Life should run very smoothly, although I’ve heard the OpenGL is a little buggy. Plain ol’ deathmatch is a little dry IMO (nothing better than Unreal Tournament for that) but two excellent (and free) mods – Counterstrike and Team Fortress – more than make up for it.

I’d think UT and Quake 3 would be too sluggish, and the server would more than likely choke, but you might be able to make them playable by turning down the visuals.

If possible, think about getting Geforce 2 cards. The off-brand ones are pretty cheap at $70-100, and the improvement could be dramatic. More RAM, which is dirt cheap these days, wouldn’t hurt either.