as a registrar i would say Moniker for sure, their communication is the best also, they are human! unlike other registars
thing is though o/p is mentioning sites, not just domains. well, rules of thumb is you don't use registarrs for hosting as its crappy and expensive.
in actual fact, you gotta be very careful where you host as theyre the real 'anal' ones
i take it you have seen the latest nightmare with hostgator?
well basically they will take your site down, no questions asked after one frivolous complaint, and im not talking legal emails, one forom an individual. you see what may appear a big form like hostgator.com, they are actually a reseller themeselves and go by the planets set of rules.
you need a private dedicated server . im lucky i have a friend who sorted me out, i have to pay, but its basically a private service where i dont have to worry about crap like hostgator etc
so think thats your best best, being with one of top registrars like moniker or enom and having private hosting