I've often wondered if, when dealing with the Mountebank's attack, you aren't better off trashing the copper than the curse (if you can only trash one), so that you have the curse to react to more Mountebanks being played. Sure, copper is better than curse, but if it's a pseudo-moat as well, then there is a discussion to be had. Also, copper isn't terrible if you're aiming at Duchies, but if there are curses around then you need better than just copper to buy even duchies, and more still if you want to have a chance at provinces. I think in a Mountebank game, a couple of Moneylenders might not be the worst idea in the world.