The MacBook (or any of the Intel Macs) in combination with Parallels Desktop is the ultimate web development machine. Now when creating a website, it is possible to preview it in every major browser (IE, Mozilla/Firefox/Camino, and Safari). In addition, if developing for a Windows server you can run it locally. With the MacBook you can take your development on the road without giving up anything except maybe some screen real-estate.

It appears that you can run IE 6 through WINE on OS X as well, although it is a bit buggy at the moment according to reports. That could be a good option for folks who don’t want to spend the money for Parallels and/or Windows.