g1smd - 1:22 am on Apr 3, 2011 (gmt 0)
The . matches ANY character and \. matches only a literal period.
The .* forces thousand of "back off and retry" trial matches. Use ([^/]+/)+ to parse the URL once from left to right, very much faster.
Add the [L] flag to EVERY rule, otherwise you can trigger a nasty Apache bug.