I definitely recommend having something that involves tickets, but the best approach is to cover as many options as possible for the ultimate convenience of the customer, not for yourself.

A good hosting company should offer direct physical mail support (though no one ever uses that route), fax support, phone support, live chat support, email support, onsite ticket support, a thorough FAQ system, forum support, and anything else that you can think of to help the customer.

And it should all be integrated in an organized manner into a ticket system so that the customer can always check up on the status of even resolved issues of theirs and so that any of your support staff can review their entire issue history, even for seemingly unrelated issues.

The more you invest in supporting your customer, the more they will be willing to invest in supporting you, simply put.