There are the obvious answers, of course, about what people are looking for when they purchase hosting. There's been a lot of speculation, though - reliable servers, lots of features, reasonable prices, etc. One thing that is almost always overlooked is "relationship". Cultivating good relationships with clients is the best way to keep existing customers and attract new business.
While we can't ignore essential elements of the business, like uptime and security, we must always remember that those faceless clients who subscribe to our services are real, living, breathing people with very real feelings, worries, and concerns. The better we can get to know our clients on a personal basis, the better we can address those worries and concerns. Aside from the monetary benefits of fostering an atmosphere of goodwill, there are some really wonderful personal benefits as well.
If you truly enjoy other people, when you sit down at your telephone, it will show in your voice, and the person on the other end of the line will hang up feeling that someone who really cares paid attention to them and their problem. Here's the catch, though. You can't fake it. People are incredibly perceptive, and they'll immediately brand you as a phony if you're not sincere. If, however, you really do like your clients and enjoy interacting with them - the benefits to them and you will exceed anything you can possibly imagine.