I prefer SuSE myself, but Debian is a great distro.
Just pick a distro that has the stuff you want (it varys distro to distro), and go at it.
Mandrake is supposed to be easier to install, but I've never used it. Alot of folks like
RedHat, but I can't stand it (I haven't used RH since the early versions, so maybe it's different
nowadays). Personally, I think SuSE is easy to install, and I like what comes with it, but others
don't.
Linux is Linux. The only differences in the distros are what software packages come with it and how
easy it is to install. So....there is no best distro, it's all a matter of what you prefer and what you
want.