The only way for the highstreet to survive is to offer something that can't be done online. That essentially means experience shopping. Going to a town centre store should be something special, something unique, whether that's in the service that's offered, the way things are laid out or something else, but the days of just being able to slap goods out and hope for the best are long gone.
If I was trying to rescue HMV now, I'd seriously consider trying something way out there. Turn much of the stores from straightfoward retailing to live performance space, recording spaces etc for local acts, start allowing/Supporting local acts to record their material and sell it, starting with locally and slowly branch out the successful ones into other stores further afield. Start getting people in to run music lessons for children and adults, get some refreshments going, make HMV not just about other people's music, but about your own, and what you'd have, if it came off, is a national chain where it's worth going into branches in other towns because much of the driver is about the local area, the local trends and so on.
It might fail disasterously, and it might not work in every location that it has, but it would truly make it something that couldn't be replicated online, it would be an event and an experience to go into an HMV store.