I would have to say MIke Martz..................
Oh wait, this is best coach, in that case i would have to say joe gibbs for the simple fact that his record is 124-60 and he is 16-5 in the playoffs and only had one losing season with the skins and that was 7-9.....He makes a group of average individual players play like a team that can not be beat. He is one coach that gets everything he can out of his players.
From a fantasy stand point, i would say you cant go wrong with Dick Vermeil coaching your team. Look at the offense he was running in St. louis a few years ago. basically the best fantasy back, QB, and a very highly rated receiver.
Now look at the offense he is running in at KC. the best back, very good qb, best TE, and the receivers.....cough. cough, well anyways how bout priest, gonzo, and green