A visit occurs when an individual (or spider) comes to your website and looks around a bit. He may go to one page or he may go to 100 pages, but he is only visiting your website once.
A view refers to the number of pages that were seen during that visit.
A hit refers to the number of physical resources requested from the server during that visit. Pages are made up of many items (images, text, etc). Each of those is a hit, while a view is the page itself.
Think of it like a book store. A person goes into the store (visit) and picks up five books to buy (views). While he is holding the books, he flips through them and looks at a few pictures (hits). So he would have one visit to the store, five books handled during his visit (views), and maybe 30 pictures he looked at (hits).
So which value is more useful? It depends on the use of the information. If you're in marketing and you're striving for bragging rights or high activity numbers, use hits. However, if you are using your stats to actually identify trends and the personal impact of your site, use views and visits. Hits can always be inflated artificially by adding a few more images to a page, for example. Visits and views, however, represent people coming to your site and the number of webpages they saw, which is much more useful for analyzing usage patterns.