Wire transfer. and be able to wire transfer ENTIRE account or transfer BTC out IMMEDIATELY.
Why would I want to leave money in an exchange account for any longer than the time it took me to pull the trigger on the trade?
So, you wan't more BitInstant-esk sites?
I want an exchange window like you see in EU cities (changed 10,000 EU to USD no problem in rome), or you see all over china (same thing 1000s of USD no problem) and you see EVERYWHERE in Hong Kong.
Why do you need an exchange? Does silver have it's own exchange? Wheat? Lumber? NO.
So, as soon as bitcoin becomes mainstream enough to be listed on a REAL exchange, Mt Gox and the rest of them are irrelevant but the money changing windows still have use to people. So, why would anyone (who has a brain) invest money in the LONG TERM in a bitcoin exchange? It is NOT a long term business if bitcoin turns out to be real and if BTC is NOT real, then it is not a long term business either.