I'd like to chime in and, with reservations, also suggest Coinbase. I had no trouble whatsoever buying and selling for months until once when I tried to buy something like $3 worth of bitcoin using a bank account that I had closed and forgotten to delete from my Coinbase account. I don't think there was actually any money at risk for them, and it was my stupid mistake, but they closed my account with no questions and no chance to appeal. I was kind of disappointed, because I liked their service a lot.
So good luck if you do use Coinbase but be careful. They watch what you're doing with your btc and they'll close your account without hesitation.
:-) Thanks for the heads up! I just actually got setup with coinbase waiting for bank verification. Yeah the only thing I'll be doing with my bitcoin from them is spending here in the marketplace...lol So they can watch all they want :-)