Although somewhat different from the opinions mentioned in the previous posts in this thread, there is another aspect of contact printing that makes it absolutely central to the whole photography experience.
The contact is where you actually study the result. I never start enlarging after developing the film. First of all, I make my contact sheet and take a thorough look into it. Sometimes I mark one or two photos I like. Then, I leave it for 2-3 weeks, just to let the thoughts associated with the moment of taking the picture fade away. If I still like the same pics, then I will print them in 10x15cm. Leave them for 2-3 weeks and if I still like them, then I say I have a picture worth enlarging.
As you can understand, I am talking about the 135 format, making it more difficult to actually "see" the picture behind the contact.
Oh, and another thing: contacts might flatter the image sometimes, but in 99% of the cases, you can see a good picture from the contact.
All in all, a very educational process in photography.