The only answer for me is everywhere!! If I am anywhere my Sony Reader is with me, it has started to become a joke amongst friends and family. (Except the bath, I get those "prune" fingers much to quickly, I don't like to spend too much time in there.) Though I do have to say I want to get this done for my PRS-505 so that I can comfortably sit by the pool or ocean to read.
http://www.golden-shellback.com/