The current availability of where I can spend with BTC is my biggest issue. I know time will tell but that is my biggest issue right now.
On another note, long confirmation times is another issue that could be dealt with.
The biggest problem with me is that in my country no one is aware about the bitcoins and that makes me really worried that where should i spend my bitcoins. No doubt I use it for online purchases but I really want that the merchants in my country should start accepting it as a mode of payment