In OS X if you press CMD + TAB you switch to your most recent application. If you press it again you switch to the application you were just using (because it becomes the most-recent).
In Textmate, if you press
CMD + `, release, and then press it again it continues cycling through windows and does not go back to the most recently used window.
I understand that I can use
CMD+SHIFT+` to achieve the desired affect, but it would be better if there was a setting to change the default behavior.