I use a reseller program run by Reseller Panel (www.resellerspanel.com/ .

I've been using their services for five years and never had a bad thing to say about them.
Here's a short rundown of their best features:

- 100% integrated into your own website design
- OR - you can use one of their many prebuilt stores which take all of a couple minutes to set up and can be customized with your own headers, navigation and footers.
- The best customer support I've found with any company (In five years I've never waited for more than an hour for an email response)
- 100% branded in your company name (including all emails, billing, client admin areas, etc).
- full control over pricing
- full control over your client's account
- billing can be through your own processor or let reseller panel do it for you.

I work with dozens of resellers and affiliates for various products and services. By far Reseller Panel has been my best experience.
You can see how I use it for my site here (www.bluegelmedia.com/hosting.htm) but to be sure it can be done better than this.

I'm a GoDaddy reseller, and the reason I signed up for it was simple. Not to make big bucks, but in order that I could more efficiently get clients signed up for domain names, hosting, email, SSL certs, etc. It got to be the hugest pain in the butt to have to maneuver through countless control panels from different hosts. Everyone puts the tools and options in a different place, some call it one thing and others call it another. I'd spend 20 minutes trying to figure out how to forward a URL, or create a subdomain. I offer it as a convenience to both them (because I can now more effectively help manage their site and answer questions) and for myself (it's easier to go to the same place every time!). That said, I have made a few hundred bucks, that would have otherwise gone to someone else. So I'm happy with it.

I know GoDaddy is not always popular, but I personally have never had a problem with their service and their customer reps are available 24 hours a day (unlike some other hosts I've dealt with!). So I can tell my client, "Oh yes, of course I can set up your hosting or email to do such-and-such --- while in the back of my mind I'm thinking 'yikes!' -- I just call the 888 number on my hosting site and the customer reps walk me through it." lol.