I'd have to say the Lovepedal Eternity and the MI Audio Crunchbox. The two cover off pretty much all my OD/distortion needs, and they stack very nicely too.
The most used pedal I currently own is my MI Audio Crunch Box. Next, is my Dunlop Classic Crybaby Wah.
I'm currently rebuilding my pedal board. I dumped all my old stuff because it was geared for one particular sound. Now working on building a more versitile set up.