I'm always amazed to see people saying things like "I bought in at X, it's now X+10, I might sell if it goes down to X+5 to lock in some gains, or at X+15, cos that would be a great profit", or various combinations of that. Unless you are performing very disciplined market making in a volatile market, such behaviour is going to at best even out in the long term, before fees are taken into account. After fees are taken into account, you are going to be way, way down.
What about taxes? You're earning government money when you're selling those bitcoins so I guess you'll have to pay taxes when you cash out (at least when it's a significant amount like $10,000+)....