Mac PowerWhatever Laptop with 4 cores.
Vmware ESX Server w/ OSX, Windows XP as the main OS’s. And at least one linux flavor too.
Also Vmware should dual boot with another small partition of either XP or OSX for times when you ESX Server truly wipes out performance of the hardware. For example, 3D intensive tasks.
Probably put an image of Win2k3, OSX server on there for development.
Next hardware option for workstation laptops:
2 hard drives for:
a. Raid 1
b. Speed: so all these OS images don’t have to share one drive.