I would recommend http://gitup.co/
I never had huge experience with this, since when I met it, I already knew git CLI well enough to get me around with just a terminal and sometimes viewing the tree in gitk with its branches.
I think that a good GUI for beginners is an excellent learning tool to get what's going on behind the scenes, and GitUp project has exactly this goal: to ease up the confusion behind what's a push/pull/remote/local/distributed/etc concepts that you just read and don't make sense (at the beginning).
IMHO, I would recommend the following: