I've got a Small-Dog brand insulated case cover for my hardshell Martin case. It gives a bit more protection from banging around and cold temps. Its got a great big pocket on the front that zippers closed and holds books, capos, strings, etc. I bought this one a few years back for $120 US. It doesn't fit my Calton case though, so I only use it when I don't want to lug the Calton around and its REALLY cold out.