I'm a big MAC fan although I do use a PC for work. I've had my current macbook for about 4 years now and have not had a single problem with it. When I had a PC I was always getting viruses, it would crash, etc. So I'm now a loyal apple fan. The Air looks amazing, and it's on my wishlist for sure (and I'm hoping the price goes down a bit too!) I saw it again on Good Morning America this week, and it truly is as thin as it looks for the Apple website. One downside though, there's no CD drive. Not sure if this matters to you, depending on how you use your laptop, but there are two options - there's an exterior drive that you can buy that plugs into your USB drive (they say it's just a tad bigger than a cd case) OR apparently it has wireless capabilities, so if there's another laptop nearby it can pickup what's on that CD drive. (Not sure of all the details - but from my research...). Anyway, not sure if that helps, but I'm not a very techie person, and this just looks too cool and will beat the usual backache you get when you have to lug your laptop somewhere. There are so many good things about it that come as soon as you open the box!
Good luck with your laptop hunt - I'd go with mac!