I'll second Debian. Spent a few years with RH then got shown the light. Not only does apt-get rock, but their security team is amazing. They got a patch out for the whole recent ssl vunerability before some of the "advanced notice" people even heard about it.
I just installed it on my laptop a couple weeks ago, and the only thing that bothers me is the slow update pace. For example, the ony stable PHP package they have is 4.1.2, although 4.2.2 is in testing.
Its useful to remember that most of what they call testing, others call stable. In many cases I'm willing to run production systems on Debian "testing".