Sorry, it's me again, with another suggestion! I think this one would be fairly trivial to implement, and could be very useful: to add a function to the upload form that automatically calculates the MD5 hash of the uploaded file. This would allow us to verify the integrity of the file, both as we upload it, and for downloaders.
I don't think this should present a huge issue, as PHP has the function built in.
Opinions?
Edit: While discussing changes to the upload form, it might be a good idea to automatically replace spaces with underscores, or disallow files with spaces in the name, as this seems to break links right now.