I don't believe Hermit Crabs should be kept in captivity. Here is my reasoning:

In the wild, these are very active, social creatures. In captivity people usually buy them such tiny enclosures. Many of the customers who come into my workplace won't even spend $20 on a ten gallon aquarium! >.<

The BIGGEST reason I think hermit crabs should be left in the wild is this: In the wild, hermit crabs frequently live to be more than 75 years old. In captivity they rarely live to be four years old.

I had a few of these briefly in my childhood, and if I ever get them again I will have a BIG enclosure, among other things. I odubt I ever will, though, because selling these animals in the pet trade is a waste of most of their life, and I would not want to support it.

On a completely different note: I really enjoyed them when I had them. A quick spritz of water and they were up and about and all over the place. I was wary of handling them after a few pinches, but I definitely loved watching them. Maybe someday when we learn enough about them to take care of them properly I will get some more.