Heh, just played an interesting FG game:
Apothecary, Baron, Fool's Gold, Forge, Lookout, Mine, Possession, Potion, Saboteur, Treasure Map, Vineyard
oppo opened Baron. I thought it over and decided that hey, if he gets 10 FG's, my Possessions will really rock. So I duly opened with the dreaded Potion/Copper...
Opponent spent the next few turns getting the FG's, as expected, while I bought apothecaries and possessions. Turns out, there's a very interesting mechanic with Possession and FG: if on a Possessed hand I pick up 4 FG's, I can play 3 of them, buy a Province, and since I'm now the one gaining the Province, I can "trash" the last FG for a Gold...
I probably significantly misplayed after the opening, but man, is it ever fun to possess a 10 FG deck!