sftp is nice, but require that you give an ssh access to the people you want able to retrieve files. Even if chrooted, it still bother me a bit.
I do like the directory listing approach (and that is actually how I do it today. This, however, doesn't allow pushing any data. I wish there was a simple way for browsers to use PUSH requests without having to implement a script server wise... Like you right click on a page, choose "send files to link location...", then select some files in the explorer and click ok. Browsers have been there for years, HTTP is the main protocol for network communication, but we can still barely use it!