I make my living from the PC's so can I say a foul word against them? Of course! PC's have traditionally lagged MAC's in hardware innovation; indeed a careful study of the industry will reveal that almost all of the hardware improvements-outside of processors-have brought to the market first by Apple; SCSI, USB, Firewire, high-end graphics, virtual computing, all saw the light of day first on a MAC.
That said, PC's have always been a less expensive game to play. PC's have traditionally been bundled with everything you need to get up and running, with the MAC's, ala-carte method of putting together a computer, one fast runs out of money.
The MAC OS is admittedly easy to use, but Windows XP is an excellent OS as well. Admittedly Vista leaves a lot to be desired, but Microsoft is already working on its replacement. I have thought about purchasing an i-Book, but I am too closely whetted to the PC to change now. And when PC's work-with the right OS-they work well for whatever you choose to use them for, graphic intensive or not. And like it or not Microsoft has made the PC dominate based on the strength of the software available for it. MAC cannot match the breath of applications made for a Windows-based PC.
And in the Enterprise environment, forget about it!