Running Windows and Linux here at the office. I'll probably move over to Linux on all three machines by the end of the year and just VM a windows install for testing.
At home I quad-boot XP, windows 7, Linux and Hackint0sh.
I also VM'd OSX on my W7 install for when I need to check my thumb drives that are mac formated. And yes, I own (purchased) a legal copy of OSX.
Since you're buying a new computer, I'd suggest going with a i7 PC. You can easily pick out the same parts they put in the Macs and run OSX on it trouble free for the fraction of the price. Laptops you'll have to research which ones have less headaches loading OSX on
