Godaddy is fine if you're not scared of horror stories. Most people don't have problems with godaddy. Coupons sets .com prices to 6,99$ + icann fee. Also there's coupon for 6,99$ domain transfers.
Coupons:
http://www.webmasterinter.net/?s=godaddy
If you're willing to pay more for good sleep at night, go for Moniker. Monte Cahn is one awesome guy in domain industry. And he's always willing to help no matter if you got 3 domains at Moniker ro 20,000.
Moniker posts:
http://www.webmasterinter.net/?s=moniker