I used to use deepbit but then switched to BTCMine, and finally bitcoins.lc. They are the best so far, the interface is great, size around 400GH/s, 0%fees, no payout confirmation period, very accurate MH/s estimations for all miners, they will also soon add buying and selling capabilities. At the moment, miners still have auto generated names/passwords, but that is going to change soon too.