Right this is draft four of my attempt to respond-Yeah there are so many to chose from that you are overwhelmed before you even start. Recently I have used FreeBSD, Ubuntu, SUSE, Gentoo and tried to use Fedora Core but it wouldn't boot after install. In all cases I wanted the Gnome environment and apart from minor niggles e.g. couldn't get dual screens working in FreeBSD or that Gentoo and SUSE used an older ver. of Gnome, I was happy with them. Well maybe not with SUSE, thought it looked ugly.
But, functionally, all worked and were completely usable as a desktop and development platform. If I'd have to recommend one I'd say make a choice for either Gnome or KDE and then pick that flavor of Ubuntu as it really is the most user friendly in my opinion.
Why am I currently on Zenwalk? Well I installed it to try out Xfce and was so impressed I stuck with it. I'll probably end up moving to Xubuntu which also runs Xfce but I'm happy where I am at the moment and can't think of any reason to switch.
Renegade: re. the reliability of Ubuntu as a server. At the end of the day its no doubt using the same-ish versions of the key bits of software so it is probably as reliable as any other *nix.