Great list. I'd like to mention I use Tower app for a Git GUI. I especially like that it shows a diff right as you're looking at changes and lets you stage chunks of code which I find very helpful.
I've actually tried Tower but I prefer the simplicity of Gitbox's UI.
If you like Tower, you should check out SourceTree (http://www.atlassian.com/software/sourcetree/overview). It's free from the Bitbucket people.
One of my biggest problems is that all of these programs seem to emphasize pushing, pulling, merging, rebasing, etc. But I don't want any of that stuff, the command line is awesome for all that. I just want to search, browse, and compare commits a bit more easily.
There are a few small things Tower is still missing, but the Tower team have been really responsive and receptive to implementing those changes when I talked to them (which I think is a benefit of actually having to pay for the app).
Some may like GitX (L) -- free and open-source. http://gitx.laullon.com/