I picked up a 500 GB a few days ago. When I first heard about the Time Capsule, I was convinved I would get the 1 TB version, but after time to think of what I would use it for I realized that I would only need back ups for system wide failure and needed to reformat, or deleting something that I need. What I won't need is something that has not been on my harddrive for over a month, decided to save the money and go with the 500 GB. Besides, the whole point, in my opinion, of the Time Capsule is to free up laptops from having to be straddled down to a desktop with external devices attached.
The concept alone of the Time Capsule blows me away, that's why I knew I had to have it. Now I can save the money to buy an Apple TV, that is, if I can convince myself I need one.
On a critical point, the only problem I have had up to this point with the Time Capsule is that i have noticed twice that Time Machine was not backing up, had to go in and choose the Time Capsule as my back up. Hopefully this will be fixed in an update.