I bought ($19.95) a JustWireless from the Apple Store. It is 10W for the power needed by my iPad and works in the week I've had it. I had a Belkin with the coiled power cord, but returned it for this one because of the detachable cord.
I ordered one of these from Griffin. Griffin has always seemed to make quality products IMO. If you search around you can find a coupon code for $5 off.