Following several recommendations I got on HN, I've moved all my domains to Namecheap. It's been pretty solid thus far; haven't had any real issues that I can think of. It'd be nice if their site was a bit less spammy, though.
The DNS and email forwarding interfaces are quirky (especially if you're trying to manage multiple domains at once). But, hey, they don't charge for those.
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Yeah, except if you use them for dns -- which I prefer to leave on my registrar -- they're assholes who spam everyone who mistypes a subdomain. Better yet, they throw ads on there and pocket the money. Cute, right?