Sent items in GMail and Mail-IMAP

GMail's slightly funky IMAP implementation is bugging me. I've got it configured in mail pretty well, but I end up with sent items in my label/folders at least when I reply. So, for example, if I label an email "important" it ends up in an "important" folder. But if I reply, then the sent item also shows up in that folder within Mail. I know that this results from Gmail's use of labels rather than folders. It's not a problem in the Gmail/webmail interface because of the threaded display. But what I'd like to do is set a filter within gmail that basically strips any sent mail of all other labels so that when working within Mail I don't get the sent items showing up in the inbox or labels/folders.

Ideas?