DELL, Mac has horrible programs and no gaming. I use a dell that was free (albeit is sucks) and I'm fine with it.
If you get a Mac you can install Windows on it using Boot Camp which I believe now ships with Leopard.
but then you would be paying more for less hardware, that's locked in then installing the same windows problems everyone else has bootcamp is nice enough for some things but dual OS on mac hardware seems a bit off, especially since the major reason aside from some software exclusive for mac is it's ease of use for beginners and such
i use a mac, they are fast, but i get a lot of problems like programs randomly shutting down for no reason, or it just freezes. Plus, a lot of programs don't work on macs. But... they are fast, and work well most of the times, just a little more expensive though.