Ack gives some pretty useful tips (I have a Mac Swicher handy tips doc on my desktop for easy reference as I'm away from my MBP for months on end, my current environment is Windows only, unfortunately).
I made the switch two years ago, and love it. Prior to that, I had owned an Olivetti, a Toshiba Satellite, and a Sony Vaio, all very fine computers, but the Windows system and the viruses, spam etc really annoyed me, even though I had purchased the strongest anti-virus/spam/malware package I could find.
My reasons for switching were the fact that Apple honour their guarantees (two iPods had died within warranty and were immediately replaced without a murmur, or an attempt to seek refuge in contractual small-print), the stunning design, the fact that I was very impressed by iPods, and the fact that Apple appeared to be virus free, - which I had thought was spin, but turned out to be true, (and was a major problem with Windows at the time, although it has improved since). I'd advise that you get Office for Mac, as well, as a lot of the rest of the world uses Word.
Since then, I have had no problem at all with Apple; indeed, my only problem has been that my current and previosu work environments were exclusively Windows.
Besides, MR is a very useful (and helpful) resource, for everything and anything to do with the world of Apple, as Leekohler has already said, so feel free to visit and ask questions.
Cheers