Make sure you try OSX before you purchase, if you haven't. It could be disappointing going from one operating system to another. Just lots of little things not being where you're used to could get annoying. And then getting alternatives to programs you've been using for years.
Good points - thanks. I've been using Windows since v1 and Linux since, oh, I don't remember. So I've been planning this for a long time and I know what apps I can and can't replace. But thanks for reminding me. Primarily the laptop will be for development and garageband, as well as the usual browsing/email etc.