If you want a community driven distro that is easy to update, I have two suggestions: Fedora Core 2 and Debian Sarge.
Fedora will be the easier of the two to get up and running. After you do the base install, goto http://ayo.freshrpms.net/
and download and install the latest version of apt. The apt package will allow you to update very easily.
Debian Sarge will soon be graduating to 'Stable' status in the Debian community (right now, it is 'testing,' but with the testing process of the Debian community, their testing is like everone else's stable). It contains fairly recent software, and is very easy to update with apt (comes already installed). Debian is a little more of an 'on your own' distro.
Just my two cents.