Tip #1: Do not buy anti-virus software and stop worrying about spyware.
Tip #2: Download Firefox. It'll give you a nice choice between browsers.
Tip #3: If you miss any old PC programs that are not available for Mac, pick up VMWare Fusion. You can find an OEM copy of XP on eBay for $90. This will give you the best of both worlds. Well, at least the best and
the other world if you need it.
And finally, Tip #4: Don't beat yourself up too much over waiting this long to switch.
Congrats and enjoy your new MacBook. I just picked up one for my wife for Christmas, despite her telling me she didn't need or want one. She currently has the 12" Powerbook. A great machine, but I think she's going to appreciate all the enhancements on the MacBook. Not to mention, thumbs up to Apple for making the Macbook line more like the MacBook Pro line. It made my purchase decision that much easier. No offense to the previous generation owners, but I probably wouldn't have pulled the trigger if these were not aluminum.
-Chris