(currently using Coinbase, they charge 1%+15 cent)
I haven't tried yet but I'm thinking transfer them to MtGox and sell them there and then use Dwolla to get them to your bank account. Dwolla has very low fees.
However you have to get verified at MtGox which can take a couple of weeks at this point. I started out #23000 in the queue but down to 13000 after about 4 days.
But this is my strategy and it will hopefully have the lowest fees, even though may take awhile longer than some other options.
Mt Gox lost my business when pressing the sign-up button constantly showed an error page. Recently opened a CoinBase account, still waiting to verify, but seems like a great wallet/exchange if the deposits end up being fairly quick. My $0.02.