Via Technometria, I would suggest that if you swap Mac for Ubuntu, you've got some very solid advice.
Todd Ogasawara has some good advice for Mac Switchers that might keep you from lamenting your move. I switched in 2002 but had never really been a Windows user (Sun mostly) and I knew Unix cold, so switching wasn't such a big deal for me. But if you've been a long time Windows user and think a Mac might be fun, read Todd's advice first. I love number two:
2. If you do go cold turkey, don't drag your wife, girlfriend, significant other, parents, child, best friend along for the ride until you begin get comfortable with Mac OS X yourself.
From A Brief Guide for Mac Switchers/Try-ers
Referenced Wed Jan 07 2009 07:32:21 GMT-0700 (MST)
Wait until they ask. That's the best way. And they will ask if they see you having fun on your new Mac.