ELPA
It's too bad ido doesn't learn like Quicksilver did. You could type qrr then select query-replace-regexp and after 2-3 times of doing that it would learn that's what you want to come up when you type qrr.Btw I use ido-hacks.el which I think gives me the beeifnts of smex on M-x but last time I compared smex was slower.