Tim Pope argues for a particular Git commit message style in his blog post: http://www.tpope.net/node/106.
Here is a quick summary of what he recommends:
Regarding “thought leaders”: Linus emphatically advocates line wrapping for the full commit message:
[…] we use 72-character columns for word-wrapping, except for quoted material that has a specific line format.
The exceptions refers mainly to “non-prose” text, that is, text that was not typed by a human for the commit — for example, compiler error messages.