Well, here i am typing away on my Mac quite happily and I'd recommend it to anyone. They say that once you go to a mac, you never go back.
Firstly the disadvantages. Not being a pc, you won't get any Microsoft applications with it, So if you want to send work word docs to work on at home you'll ose all your formatting etc. You can buy MS for mac though so that should get that sorted.
On to the best things about macs. Well sure, buy a sony if you want to expose yourself to all the viruses out there on the web. Macs don't get viruses! Also, the applications are great. ITunes is standard. Iphoto can talk to almost all digital cameras as does imovie with camcorders. There's also iweb for super-easy posting stuff on a website (I use a dot-mac account). Quicktime is standard and Garageband is great fun to make up your own music with. There are a few differences but you get used to them pretty quickly.
Go for it mate, you won't regret it. I love my ibook and I will be upgrading to one of the new super-fast Macbook pros soon.
Hopefully I hav helped but then again, I'm biased...
