'Nix works best
New 64 bit home built AMD AM2 socket machine, instantly responds with one of the 64 bit Linux OSes. Mepis 6l5 -64bit is fine, here, since May.
Older Macs (iMac 700mhz w/512MB RAM) runs great with OS 10.3.9.
Fedora Core 7 and Simply Mepis 6.5 for 32bit systems work great on 32 bit PCs of 500 Mhz to the 2000mhz boxes, in schools.
Safe, secure, and fast fun for all the students, with no service calls in the past year of 48 deployed in a local private academy that lives online with research and discovery!
http://livecdlist.com has ~300 choices in Linux Live CDroms, each complete with thousands of suites of applications!
Too bad Vista was such a pig in a poke, but, it isn't missed by intelligent teachers and students who simply want efficient tools with which to learn.
We'll spend our money on beefing up some of our older computers, and sales reflect this.