http://www.starcraftwire.net/blog/comments/collectors-edition-qa/ Submit your questions and maybe you'll get it answered in a video released with the collector's edition. That would be a great honor, in my opinion. Also, what's more is that a Collector's Edition has been confirmed (not that there was any doubt) so that should be good news to collectors.
Now let's hope that the collectors edition is more then just a fancy box and a video. The video wil be all over the internet on the first day, and a metal box doesn't fit in my cd hold thingy. I hope for a paper strategy guide, or some other things you can actually hold in your hands.
Metal would be nice, but not for the Protoss. Their music should be similas to the Night Elve music from Warcraft 3. A little mysterious, but also sounding like an ancient force, that will destroy anything that opposes it.