The Macintosh computer, along with Apple as a company, has always had its home ground in the creative fronts, mainly because the tools for image editing and desktop publishing were either Macintosh exclusive, or ran faster on the Macintosh at the time.
Personally I prefer working on the PC, mainly because the enviroment is more familiar to me. Although I have used Apature on my MacBook, which is pretty slow in comparison to my computer, and I really don't have many photographs that I can edit on it really so it never got used.
I use photoshop for just about everything, so i'll probably stick with it
Aperture is a good application though, they should bring it out for window though!
Canon EOS 5DmkII + BG-E6 + Canon EOS 40D + BG-E2N + Canon EOS 33
Canon 17-40 F/4L
USM + Canon 24-70 F/2.8L
USM + Canon 28mm F/1.8 USM + Canon 70-200 F/2.8L
USM IS + Canon 85mm F/1.8 USM
Canon Speedlite 580EX II + Canon Speedlite 540EZ + 2 x Nikon SB-80DX
Cactus V2s Wireless Trigger - 5 x
Cactus V2s Wireless Reciever