I have a Compaq Evo, 1.4 GHz with 512 MB RAM now and I have been given the go ahead to get a better one. I am going to be using it for video editing, remote server repair/diagnostics, and gaming (when I'm at home). I have a wireless network set up at home and I am going to be putting in wireless in the 2 main buildings.
Minimum of a 2 GHz, prefer 3 or better
minimum of 512MB RAM, 1024 preferrably
Floppy (lots of newer ones leaving this off)
Decent graphics card (128 MB or better)
at least 15" screen
Minimum of a 60GB drive
And of course I want a reliable computer above all.