You have to be prepared for this possibility. Create some incentive for the client to re-visit your site, such as an upcoming update on interesting content. In general, don't worry too much about the wishy-washy visitor. It is the logic behind the new super bookstores. They are comfortable and friendly to visit.
People read books in the aisles, many times visiting without purchasing anything.
The previously wishy-washy visitor will become a customer. Even if your wishy-washy visitor doesn't yet wish to purchase, you can still make him or her take some action. Perhaps you can encourage him to bookmark your site or make your homepage his start page. Or perhaps he can be directed to a friendly site featuring more of your work, an article praising your work, or content subtly reinforcing your sales message. Even smarter is enticing that visitor into an informational e-mail or call.