I've been running it at 1024*768*32. TI 4200 running at 257/500. 1Ghz & 512MB ram. Looks good, plays well (enough for me anyway). I've noticed a few slow downs here and there, but I think it was lag.
I'll be upgrading my mobo, ram, and monitor soon (not for this game, but just becuz there getting a bit long in tooth).