A really useful topic.
Actually there are lots of hard cases on ebay, but in my opinion they adding unnecessary bulk to the phone which is not quite slim itself. So from day 1 I've been searching for a good thin (probably silicon but could be other material) full body cover.
So to add to your list, the first one that was out there since the phone launch, the Amzers silicon jelly:
I have this one, it's nice but all that surface relief adds a little bit dirty look to the phone
Also just found not badly-looking one by Capdase: