I always appreciate commit messages that are informative and well structured. That said, I'm not a fan of specific formats for commits. The commit messages in a project are where a lot of that project's collective "personality" is stored. If you look through the commits for a project with a "colorful" variety of messages, you'll get a sense not only of the work that was done, but of the people who helped create the project.

Somewhat related: @git_commit_m on twitter has some great (and amusing!) examples of what not to use for commit messages, which are pulled from github's public data set.