Search your email!

One of the features that most of the pretty GUI mailers offer you is the ability to search your email. While this is not a feature I use regularly, it is one which when you need it, you really need it. I have used grepmail (was at grepmail.sf.net) in the past, but it slow for me (it scans the mail files every time) and the big thing for me is that is only supports mbox files, and I use maildir since I use offlineimap.