Anywhere between .84 and .99.
.99 has the Golden Tee games and the Robotron video speed fix, as well as hiscore.dat support.
My bartop has .84 on a P3/833 with 512meg of RAM and a gutted version of XP and MaLa. It has a Stargate control panel and I just run a limited set of ROMS, but all the classics and even the not-so-classics like Gigawing and Mars Matrix run fine on this setup.
Since all 3 of my MAME machines have been based on hardware that was thrown in the closet while upgrading my desktop machines, the thought of buying a new computer specifically for MAME seems kind of odd to me. I also feel MAME started getting worse with every "upgrade" around .100, so perhaps my perspective is a bit skewed.
