I voted for GoDaddy. I'm voting with my feet also. All my domains should be at GoDaddy by the end of the year. Why? Best Control Panel and Cheap Prices. OK, their TOS is a stickler, but most of the people who fall fowl of their ToS are using GoDaddy for Hosting. We are talking about Registration here. My biggest complaint would be their checkout. They were supposed to be coming out with an express checkout for preferred clients but that never transpired. The express checkout they have is pretty much pointless since it defaults to 2 years.
Next I'd say Name.com and then Fabulous. But even with hundreds of domains at Fabulous, they were not competitive on pricing. Name.com has a superfast checkout. Generally, nothing to complain about with them except I don't like the two lines per domain in you account, if you use their privacy.