I'm going to throw my vote in for RedHat. It's pretty straight forward, and has pretty good documentation and support. And after you get familliar with that junk, you can always switch over to another flavor and have a new chance to mess that one up all over again
! (Unless you're actually already a 1337 linux h4x0r, and you're trying to put on a clever rouse of being a linux newbie, which I'm sure is the case :P.)