Unity. Cinnamon is in second place for me. My only issue with Unity is somewhat poor performance. I think the next version is supposed to improve this quite a lot. Performance has already improved a ton since the initial release.
Xfce by far. It's more or less a full desktop at this point, it doesn't try to reinvent the wheel, and it can be configured sanely for low resource usage. IMO those things put it way ahead of the competition. (Mate comes second for me. It's quite nice, but it's a much smaller project than Gnome 2 was, and that hurts a bit. Also the window manager doesn't improve on Metacity's poor performance and lack of configuration options.)
i did not care much for Unity, it's not very customizable. loved E17 in Bodhi Linux. i thought Cinnamon was pretty cool. but my favorite had to be KDE.
If you can live without the bling stuff, LXDE + Openbox is great. Not typical "Unix-ugly" either, looks pretty nice actually and the speed.. man the speed.. It's even more responsive than XFCE.
I tried KDE,Ubuntu and Kbuntu,KDE was my favorite but had some wireless issues.I just got done burning ubuntu and I have a bunch of DVD to burn so plan on making some other distros for testing.I just need a bunch of computers just for linux so I do have to choose which one.
I just realized I had a few mistakes. Both Unity and Cinnamon should have GNOME 3 in front of them. As for myself, I like KDE's glassy look. I like bling since my computer is a beast and can handle the resouce usage. However, as far as user friendliness, I have to give it to Cinnamon or MATE.