I luse a Mac Desktop G5 for some work I do and I like OS X and obviously all of the software you might need from the MS suite for writing to Quark to InDesign, Photoshop etc. runs on the mac. The one thing I will caution is that Apple is selling overpriced hardware to people who want their operating system. You can get a comparable computer with the same power as one of the new macs running the Intel Duo Core processor for a fraction of the price, but the machine will be running windows, not OS X. Apple's business model is that people want the apple software bad enough to overpay for the hardware. It's a personal choice you have to make.
As an aside, when Apple decided to build its new machines with Intel processors, instead of on the Motorolla processors they had been using, they opened a can of worms. They had to rewrite OS X to run on the Intel architecture, and the minute those early versions of the operating system were released to developers the hackers got to work on it. You can actually now run OS X--hacked, patched versions that are easy to find--on any Intel-based machine. If you want to go to the trouble, you can build a machine with very comparable parts to the new Macs--same processor, components, etc.--and minimize the chance that some components don't work with the hacked operating system. The machine you build will cost a fraction of the price of what Apple is charging. I know most people aren't going to go to that kind of trouble, but I am running OS X on an old Dell laptop that isn't even optimally set up for it, and it runs fairly well. I did it just because I could.