Update: This answer has gotten far more attention than it deserves. It was originally posted because I think the graphs look nice and they could be drawn-over in Illustrator for a publication– and there was no better solution. But there now exists much more applicable answers to this Q, such asfracz's, Jubobs', or Harry Lee's! Please go upvote those!!

Update 2: I've posted an improved version of this answer to theVisualizing branch topology in git question, since it's far more appropriate there. That version includes lg3 , which shows both the author and committer info, so you really should check it out. Leaving this answer for historical ( & rep, I'll admit) reasons, though I'm really tempted to just delete it.

My 2¢ : I have two aliases I normally throw in my ~/.gitconfig file:

lg1 = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar)%C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(bold yellow)%d%C(reset)' --all
lg2 = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(reset) %C(bold green)(%ar)%C(reset)%C(bold yellow)%d%C(reset)%n''          %C(white)%s%C(reset) %C(dim white)- %an%C(reset)' --all
lg = !"git lg1"

git lg/git lg1 looks like this:
git lg1

and git lg2 looks like this:
git lg2