I've been with DirectI for a while now, and I've been very pleased. They're always working to improve their services and their control panel, and I think that is very admirable. Regardless, the service has been top notch with the pricing that you would expect to see elsewhere. They also accept a wide range of payment options, which is nice for those who don't (or can't) use PayPal.

In the past, I've been with eNom. I wasn't very pleased with them or the way they handled some of the issues that I brought to their attention. I haven't been with them for a while, so things may have changed since.