I'm looking for a nice, Mac OS X-like, client for Git. As an example, I use Versions for Subversion and it's exactly what I'd like to purchase for Git access. Suggestions?
You could try GitX. Never used it myself but a quick google shows a few hits where people seem to favor it.
I think smartgit is powerful and best www.syntevo.com/smartgit/index.html though it's quite heavyweight. It's commercial, but there's a free version for private use too :)
Brotherboards experimental branch 3-22-2010 ist also very very nice. Many new features over the gitx 0.7x builds. See brotherbard / gitx on github and download GitX_3-22-2010.zip
Just to add to the remarks about gitx, which I can't add as comments to the relevant answer due to not enough reputation points:
to do things like change which branch etc each version has (eg local vs on github), you do it via moving the local / github associated tags to the desired branch.
This isn't mentioned in the docs afaik, but its kinda key :)
GitX is very nice, but it is NOT EVEN CLOSE to what you're asking for. It will not entirely shield you from the command line. Some of us think that's a good thing, but you'll be frustrated if you're looking for something like Versions. I know of two GUI clients that claim to do this:
The first is Java-based, and the second is Cocoa and looks very nice, but is still in private beta, so you might have to tolerate a pseudo-Cocoa interface for now.
I used to use GitX, but it has little functionality at the time.
I'm really enjoying day by day work with SmartGit, good interface and lots of functionalities.
SmartGit also supports git-svn for those, like me, that uses Git locally and push to a SVN repo.
I hope this doesn't come across as spammy. If you are looking for something simple(like Versions) or geared towards a Subversion-style workflow, you should checkout GitMac. http://gitmacapp.com
It was actually developed to cater to developers migrating to Git from Subversion/traditional VCS. Though, if you want more of the advanced features of Git - GitX and SmartGit are nice.
I've been using Gitbox for the past few weeks. Most excellent (although still not as good as Versions for SVN).