I haven’t been a big fan of the revision system that has been in WordPress since 2.6. Yes, it has saved me a couple times, but it takes up a lot of database space, and there is no way to eliminate all the revisions.
Fortunately, a guy named goshy came up with Delete-Revision. It will go through your wp-posts database and let you easily and quickly take out all the revisions except the actual post. While it is not officially tested with WP 2.7, it does work seamlessly. The only operationally-bad part; it’s an all-or-nothing operation.