Mac's are quite expensive, they cost around the same price as high-end Sony/Toshiba PC's & Laptops. They're worth every penny though in my honest opinion. The cheapest one available at the moment is the MacBook (£699), however, a new model is due around October, so the price might drop £50 or so. I've got 4 gigs of RAM in mine, so it runs very fast, the only slow-downs i get, is when i'm running 2 or 3 programs, plus Windows Vista in BootCamp, but it's still not very noticeable, which is very impressive.
I got my Mac in January, im very impressed with it, no problems whatsoever. The operating system is superior to Vista imo. Don't fall for the common "Mac's aren't compatible with......" It's a myth, absolute bollox; the majority of software available for PC's are also available for Mac's, if you do find a program that isn't compatible, just boot up Vista/XP on the Mac and run it that way, best of both worlds. I'll only buy a PC again if Microsoft improve their OS.