I'd recommend OpenSUSE.

I've recently tested the three distros (Ubuntu 8.10, the latest stable Debian and OpenSUSE 10 or 11, can't remember now).

* Ubuntu was the most usable "out of the box" (better menus, cutest colours,etc).

* Debian has the best package management / repositories, etc.

* SUSE has the best desktop experience, after you put some order in that mess of menu system they install by default.

I tried all three systems with Gnome.