Tom says it very well.
Microsoft is expected to recommend that the "average" Longhorn PC feature a dual-core CPU running at 4 to 6GHz; a minimum of 2 gigs of RAM; up to a terabyte of storage; a 1 Gbit, built-in, Ethernet-wired port and an 802.11g wireless link; and a graphics processor that runs three times faster than those on the market today.
The second factor is Will Novell Adopt the Linux Terminal Server Project?
At Lewis, we have mostly iMacs. With a RAM upgrade, all of the iMacs can and will soon run the latest version of OS X. So as long as the Macs are running we will go the route or OS X. If I had come to a school with a majority of PC's we would of worked to move to LTSP. Of the 2 instructional PC's none have the specs to run XP, let alone Longhorn...