When I get my mail, I take it from the mail box and set it on a table inside. It sits there for several days. When I'm ready to do my bills I will grab the pile and visually sort it. Not by file name or file date, but by looking at the outside of the envelope. I can tell pretty quickly which envelope is a bill that and which ones are junk mail.

Cover Flow in the finder seems to be getting a overwhelming "meh" from those that have seen it. I think it's a great idea since it provides the same visual sorting of documents that I use for sorting my mail and other physical paper documents to the finder. It moves through documents quickly and focuses on one document at a time (unlike the icon view). I'm not saying it should replace search functions, but its another way to find something when the search function doesn't cut it because I don't know the name of the document.