A good desktop computer to run linux

What is a good desktop computer to run linux ?

have many linux machines from Ubuntu to mandriva. I did purchase a ubuntu machine from dell to support the movement and i have to say it really is awesome, but also not required. Linux can run on just about any machine. I have dells with it, emachines, and hp's.

If you are not sure your choice of distros will work with the machine you have picked out for it, try running it with the live cd version of your distro first(if it has one, most do now) and if you see problems with running that you will know before you format your drive... ;-)