Blu-ray is still growing although slowly, it's dvd that's declining more rapidly.
I don't see an alternative in digital for collecting movies long term. I can't even stream a single blu-ray quality movie a month. The last 10 days I've had to monitor my internet usage again since the kids had been using you tube too much. 80GB limit is getting smaller and smaller. Tomorrow I can download Child of light, limit resets on the 2nd. A lot of movies I like are not available digitally either, well not legally anyway.
CD is still around but sadly you have to order online now for a good selection. The shelf space for CD is laughable nowadays. No more browsing for obscure music :(
Blu-ray shelf space is still growing however, DVD is shrinking. In my local store blu-ray has more shelf space nowadays than DVD (including 3D shelves)