While I'm on the subject of complaining about things that upgrading to ubuntu 10.04 broke (see here), another problem that happened on moving from 9.04 to 9.10 (I think) is this:
Firefox used to open embedded pdf files with evince and that was fine. Now it opens them with okular, which I don't like for several reasons. (Pg Up, Pg Dn keys don't work. I don't like the KDE save file dialogue box, because I'm used to gnome. )
So my question is: how do I change which program is used to embed PDFs in firefox in ubuntu?