I find few of my fellow coworker devs know about or use gitk, and it is an awesome tool for visualizing where all the branch madness is. A lot of things that require good command-line git knowledge are a few mouse clicks or a menu option away with gitk. Undoing a merge for example (a classic "oh no, I pulled on the wrong branch and now it's all fucked up"), I've no idea how you'd do that with the command line, but in gitk it's just right click the parent commit and choose "reset the branch here".