I also want to point out that, using BootCamp, you can run XP or Vista on the Mac either after a restart or within OS X using something like Parallels 4.
I have recently got a MacBook after my old laptop died completely - dodgy graphics, constant crashes and freezes, awful overheating and restart problems etc.
I really didn't mind paying a bit extra for it - I love the operating system, but as pointed out that is something which is personal taste, and when I want to run programs I have specifically bought in the past for windows, like Microsoft Office, I can run them in XP too.
This laptop is the same speed as my old one (2.13ghz, which is kind of slow, not that I do much), but things generally run faster; Photoshop Elements loads much faster, and the thing that I am most impressed with is that things just happen when they are supposed to - things don't freeze or quit randomly - although this may have happened due to my error on my old laptop, I question why the same error hasn't occured here.
As the icing on the cake, there are loads of small things I love about my change to mac - amazing looks, magnetic power supply (as my old old laptop nearly smashed after tripping over the wire), a better quality web cam built in, a really profesional shop which demonstrates everything for you and software which I really enjoy using - garage band for example is really fun to use, when messing around with my guitar.
Anyway, just some of my ramblings XD Mike.