Recommended Linux Distros
Linux 
Mint is probably the most polished linux distro you will find. It is currently based on Ubuntu. It offers many editions for you choice of desktop environment. Currently they offer editions of Fluxbox, Xfce, KDE, and the Main Edition which uses Gnome for its desktop environment. This distro has a great community for support and an irc channel on chattingaway. If you have not tried this distro it's highly recommended you do so. You probably wont consider even using any others. It's main features are its polished user experience along with having all media/web codecs installed by default. It has a custom application menu along with all the applications you would expect in a full featured desktop. Be on the lookout for the next version of this distro. It's sure to blow you away!
Ubuntu comes recommend also. Each new release brings new features to the linux desktop. The next LTS release 10.04, is going to be great indeed. The new MeMenu and social features add alot of benefits to the user experience. The only area Ubuntu lacks in is its polish. I was hoping this problem would be rectified with the announcement of the new default themes but sadly I believe the Ubuntu desktop look has gone from not enough polish to just plain horrid. I really hope they come up with something more elegant before the April release. Aside from that the Ubuntu community cannot be beaten. The user support is probably the best as far as linux distros go and launchpad has made it so easy for packages/updated packages/latest packages that theres no other distro with as many precompiled packages.