After much fiddling, my RSS feeds all officially validate, and Firefox seems happy. While I was in there, I added my secret Atom feed to the mix, so now I have three feeds to choose from:

• RSS 1.0 excerpts
• RSS 1.0 full entries
• Atom 0.3 full entries

I still think these formats are all a pain. To make my RSS excerpts feed validate, I had to make it 30% larger by adding entirely redundant information to it. Yuk.