I have just got a MacBook Pro and have been using it (+Fusion) to develop on for about a month now. The purpose of this question is similar to Hidden Features of C#; to become
@Andrew - I'm exactly in your situation. I use a MBP while my company work is purely Microsoft based: i.e., .NET, COM etc. While nothing can beat running Vista natively in Boot Camp (I've never seen Vista run so fast), the niceties of having your Mac OS be the "main" OS, for internet, mail etc. has gotten me to the following configuration. Works like a charm:
For non development occasional need I also keep Microsoft Office 2007 installed. They do have MAC ports, but those don't always cut it.