What kind of price point are you looking at.. i.e what are you paying now? You have to look at both registration and renewal costs. For example GoDaddy provides unbelievable registration costs at times as low as $1.99 for 1st year, however, renewal costs are around $19.95.
VentraIP is only $15.95 per year, reg and renewal, for .com and has a nice control panel and great email support. And VentraIP don't spam you with marketing every day like crazy domains. I use their wholesale arm "synergy" which is a little cheaper, control panel is terrible but I have connected it to a WHMCS panel which makes it manageable.