The problem with files is that they need to have a different name, depending on context. Let's suppose I've written a travel diary about Belize. On my computer, this could be called "Belize2005_v5". On my girlfriend's computer, "PhilBelize2005Diary"; when I upload it to a travel website dedicated to Belize, it needs to be called "Belmopan PhilippWesche May2005 english" etc. (Belmopan is a place name in Belize.)
Files need to know which filename is most informative in a given context. This is addressed to some extent by meta-tags in some filetypes such as mp3 and pdf. However, I am not currently aware of any OS or desktop environment that filters out only the most informative information, e.g. test whether the file is residing in the filespace of the creator; if not, include the name of the creator in the label. I'm sure one could think of many more simple rules that would be enormously helpful, and in combination could revolutionise the way we interact with files.
Edit 24/07/05: This is of course where Unix was going all along, with the idea of uid and gid for files!