Many have talked about p2p exchanges, the biggest problem of the bat is fiat currency.
While I've seen many words dedicated to it, I've yet to see one actually build.
Let someone else deal with fiat, there's plenty of people doing that and doesn't fit well with a p2p exchange.
A pure p2p coin-based exchange should be doable with the current technology in Bitcoin. I think the problem is that there's no profit in it, by definition (at least, not more than you'd get in tips).
I'd love to build one myself, but just don't have the time (kids, man). Hopefully someone else will come along and do it... No more paying crappy websites a percent to trade virtual currencies.
