tiny XP
I've installed tinyxp beast edition on my intel mac mini. Only problem i have is that the mac drivers cd that boot camp makes for you can't complete installing all the drivers. When it gets to 'registering product' it fails. i guess its trying to get online but the wireless network isnt set up and i dont have an ethernet cable spare. so it works. kind of.
I just want to put my vote in for nLite in general. I built a new machine and went with nLite for the install and was able to strip down to exactly what I wanted. (Presumably you could do the same with the TinyXP config files.) Also, it's *extremely* handy to be able to incorporate your own chipset drivers, etc. Saved a couple of hours of install + config time at least. I love my Macs, but I can strip down and optimize XP so it's even faster. I'll say this, too: I'm staying far, far away from Vista for the forseeable future with XP doing its job.