My buddy wanted to insure his record collection and was told by his insurance company that he would require a professional appraisal to establish the insurable value. IIRC, the appraisal was quite costly and required updating at the insurance company's discretion or if the collection changed in a material way. Again, check with your insurance broker.
As for your equipment etc, document everything along with pictures. In the event of a loss, having documented proof with the make, model, serial # and pictures makes it easier for the adjuster to settle your claim.