One thing to keep in mind is once you get it, don't procrastinate registering the device and getting the most current updates as well as downloading any of the apps that interest you. It should work fine by itself once that is done even if the site goes down.
Unfortunately, this is not true. Chumby downloads the control panel *every* time it restarts. So, if they servers go dark, your Chumby will be useless. And for the record, the company is all but shut down now.
You can search the Chumby forum and find some software tools for taking your Chumby "offline" but I wouldn't recommend it to anyone that doesn't want to tinker with it.