I've never had to claim on it.. but my website was to show my collection to the insurance people. No point burning a CD as this gets out of date but a website resides in virtual world and if the host goes down then you simply upload another copy elsewhere and let the insurance people know where to look. I now have a website dedicated to my house and contents insurance that links to all my other collection sites including the smurfy one. (Help I can't escape.. I'm getting all tangled up in the world wide web).
As far as how much the collection is worth I simply referred them to some online smurf shops for a comparison and estimated my collection at around a certain figure.. ditto with the CD, DVD and chess set collections. Simply calculating via the average value, multiplied by the number of items. Not too scientific but they didn't argue. I guess when it comes to smurfs they were too afraid to ask.