May 2014: ~$2200/coin

I expect Bitcoin to be handling about 1% of World GDP by that time and the above price represents that. Difficulty will have also increased to match that. We'll be seeing second-generation dedicated ASICs coming out around this time. The people mining won't be consumers and there will be only maybe a hundred major players, most of which have government regulations to deal with and forced transaction fees to collect, however the expenses will be low.