Let's kill the suspense. Ubuntu is the winner, hands down or is at least on a virtual machine.
I installed Ubuntu and Windows 7 on oracle virtual box, on Windows XP.
Windows 7 (in its vanilla form, extreme edition) has a wait icon on mouse pointer on everything I do, and visible lag on opening anything.
Ubuntu, with all bells and whistles turned on (compiz/etc) works extremely fast and feels snappy.
I wish if some company properly designed and marketed laptops with Ubuntu for end-users and provided appropriate support!
Microsoft and Apple would have to run for their money on OS market.
