vmware esx on a desktop/workstation

Hi,

I'd like to run ESX on a desktop/workstation (Dell or HP)

Any suggestions on what I should buy ?  I'm not really interested in performance as such - two dual core processors and 4Gb ram will do just fine.  I just want to use it as a staging/test box to test patches and so on.

Does anyone know if this would work and if so, what I should buy ?

PS : I don't like the idea of buying a small server, as those boxes seem to generate more noise than a desktop/workstation

thanks