I just evaluated three virtualization product for the Mac: Parallels Desktop For Mac 3.0 (build 5584), VMware Fusion 1.1.2, and Virtual Box (Version 1.5.51) to run Ubuntu Linux 8.0.4 (Hardy) server (not the desktop version). My test system is a MacBook (not pro) with 2G of RAM and 2.2 Ghz Intel Core 2 Duo on Mac OS X 10.5.2 (Leopard). This is an 64-bit CPU and OS.