The most awful problem I'm seeing is that sometimes files are renamed as txt
(the download window show them as being recognized as text/plain, and indeed
adding a MIME type spec helps fixing them).

For example, downloading from this URL with all default settings, all rar
files are treated as txt.

<http://www.delamancha.co.uk/plugins.htm>

But browsers do correctly recognize and download them.
If I add a MIME type for text/plain -> RAR, then it works, but all text/plain
MIME files are then saved as rar.

Please fix this and you're going to make tons of people happier, of course
including me :)

- Mario