I'd also suggest going with Ubuntu and in particular a LTS (long term support) version.

Ubuntu 12.04 will be supported out to 2017 I think.

I'd also suggest if you have a beefy enough machine to setup inside a VM.  This way you can easily try various distros and figure out which one you like.  I just got a new laptop and went through a bunch - Crunchbang, Elementary, all the Ubuntu offshoots (xubuntu, lubuntu), CentOS, etc.  Ended up going with a vanilla Ubuntu 12.04 install - boring but it's stable and it works :)