well i'm capable of an objective view, owning both!
Macs are generally renowned as being better than pcs for this, as they can display more true-to-life colour - hence the fact that 99% of newpapers and magazines are made with a combination of Photoshop and Quark - i also did Media production at college :P
Methinks jginete hit the nail on the head - a mac with AGP graphics is God among desktops :D
If its only for gfx editing and your serious then a mac, if you want your comp to do anything other than gfx editing, get a PC
Racing Is Life. Anything that happens before or after is just waiting Jesus may be able to heal the sick and bring the dead back to life, but he can't do shît for low fps
And those apple laptops look so damn cool too! For image editing, if thats all you want, consider a Matrox gfx card. Seriously, image quality is so much better than Nvidia and ATi, and you can get triple head cards for three monitors. The Parahelia is still pricey (Why?!) so if you cant afford a mac, cos they cost a lot, then think about matrox. Of course, crap for gaming!
My house is filled with Apples. Just off the top of my head, there's 5 Macs in the house, and there's only five people who live here. I can't stand them. :P
If you have a new motherboard, get some dual channel DDR RAM, they will have a huge performance increase. I think these motherboards can be bought for just under £100, and the RAM is just a bit more expensive that the standard stuff.