Here is a combo I discovered today that made for a very fast game: <A href=http://dominion.isotropic.org/gamelog/201109/14/game-20110914-014113-14705461.html>Apprentice/Envoy.</A>
To set up this combo I opened silver/Envoy, bought one Apprentice and a ton of treasures and it was, like, off to the races. The heavy treasure matched well with the envoy, and I used the Apprentice to sacrifice Silvers and Golds, rather than Coppers, to speed through the mid- and end-game. All non-VP buys throughout were for treasure only, so it never stalled.