Apple and Mac have long been the systems of choice for graphics professionals. One of the reasons, Mac's had better processors than most PC's for years. Apple had 32 bit operating systems and RISC processors before Gates even had Microsoft working on it for windows. Basically Mac's used bigger faster engines than PC's for years.
On a Mac you can modify the RAM allocated to a particular program, especially useful for graphics work, as you are often dealling with HUGE files. If you have tons of RAM you can tell Adope PhotoShop or any program to take advantage of it, without extensive paging and swapping files from the swap file on the hard drive (as on most PC's with Windows).
As far as the myth that there aren't many good software programs to run on Mac, that isn't true, in the graphics area this is most definitely NOT true. Mac's are STILL the computers of choice for serious graphics professionals, ex. like in newspaper art departments. Most decent graphics programs were developed on the Mac platform for Mac's, before they were ever ported into PC versions as well.
I do tech support for a living and worked for a while for Apple Canada's Technical Answerline. I was a windows & pc person first but fell in love with Apple's, as the technology is far superior, the integration with the operating system and the hardware is much better done. I hate living in a windows world and my next computer will be a Mac laptop, it can do anything a PC can do better and faster and with less hassles.
The only trick to having a Mac is living where you can get good support for it. If you live in a small town or in a rural area, your choice is often only to get a PC. If you live near a big city with good Mac dealers - go Apple!!!!!! You won't regret it.