I find myself using mainly gitg in combination with the command line for more complicated tasks.
Source repository: http://git.gnome.org/browse/gitg.
Recently, a new version 0.3.2 has been released, which is a rewrite using Vala. It’s not yet feature-complete compared to the old 0.2 series, but the refactor is expected to speed up future development.
Also, there are normally PPAS on Launchpad which contain a more up-to-date version than the standard repository.
