I'm in the process of making the move – and I'm past the point of no return and I'm glad I did. It's not about "Think Different" – heck, I'd say Mac's are more than 50% of what you typically see at a Starbucks or startup these days.
And it's not my first Mac by any stretch – I was selling and using Mac 128K's and 512K's 25 years ago, and got the second PowerBook 540C to arrive in Philadelphia in 1994 (the first went to Barry Diller who was running QVC at the time). Even though I've always had a Mac at home for iTunes, photos, etc., I've been a PC guy for work since Windows came out, primarily because I started building my contacts on a PC. Eventually they went into Outlook where they've stayed and where I've gotten very used to Outlook email.
I've switched and combined the two now, and have a MacBook Pro 13" with as much RAM and solid state storage that Apple offers (highly recommended – it's lightning fast), with all my photos, songs, movies with me on the Mac side. And thanks to @VMware my Mac is also a really fast PC with Windows7 and Office 2010 and my email and contacts and calendar and old files just like I always had them. I'll switch over to Mac programs over time as Microsoft releases Outlook 2010 for Mac but for now it's the best of both worlds. Thanks to @dropbox I easily transferred files (including massive multi-gigabyte PST's) and can synch across machines, and thanks to @xobni all my years of Outlook auto-fill email addresses are already there. And @etsy helped me find a sticker that will look great in our New York office.
Part of the change was driven by how cool the iPad and iPhone are – and how I wanted to have them connected and synching with iTunes wherever I was all the time. Where I hope and bet it goes for my next MacBook will be one that has iPad-style multitouch plus the keyboard all baked into one – essentially doing what my old Lenovo Tablet PC tried to do but in the way Steve Jobs and Apple would do it.