Actually running the Windows OS on mac works great! Consumer reports even gave the macbook pro top spot as 'best laptop for running windows OS'. Even if you don't want the mac OS, the hardware may still be worth the investment, then throw windows on it. The Imac's, for example, have a great design - like a laptop/desktop combo, they don't have a big tower, no major cable mess, keeps clutter to a minimum, and they put some great hardware in them. You pay a premium for this though, and your dollar doesn't go as far for performance, rather - function and design are equal contenders here.

If cost to performance is your primary goal, and function/design is a secondary thought - then the ideal is to build your own PC. Getting the new i7 platform cpu will make your computer a speed demon. I personally chose this route because performance matters much more to me than function and design - though the function/design of the IMac is quite compelling.

Photoshop runs equally well on both Mac and Windows now.