Mitch Kapor: "I have replaced Internet Explorer with Mozilla as my default browser on my ThinkPad. (I will save for another time the story about my choice of PC’s. I also have a Mac and use it regularly. Where is the Linux machine, you may well ask — but as I said, that’s another story)"
I use the same configuration as Mitch. At most "digerati" conferences I go to, the two machines that are over-represented are ThinkPads and PowerBooks.
As for the browser, Mozilla and its stepchild Firebird are finally reaching their potential, some five years after the project was launched. Microsoft succeeded in killing the browser market, but not browser competition.