After upgrade to Angua, my feed was overfilled with numerous entries for media files. How to prevent them from appearing in the feed?

One way is to disable media revisions. However, these may be useful so it is a bit too drastic.

I found an alternative way. There is an undocumented new parameter to feed.php which control what appears inside it: view can be one of pages, media or both. It defaults to both. If you replace feed.php with feed.php?view=pages, you obtain the old (sane) behavior back.

If you already have a lot of people subscribed to the old URL (without view, i.e. with view=both), you can arrange this through URL rewriting, or by modifying the default from both into pages in the feed.php file.