The *.pdf filename extension should be associated with Firefox.

Maybe we may ask that during installation?

If another pdf reader is installed there's no reason to set firefox as the default. Although, to 'associate' it with firefox would be great. All it should do (for the end user) is add the option to "open with" firefox under windows explorer/finder.

We also should be able to control association in Applications tab in Options. So users can un-/associate Firefox for PDFs.

@aicitman: "If another pdf reader is installed there's no reason to set firefox as the default" How on earth would you know what reasons each and every person on this planet has for doing something one way or another??? You's some kind of mind reading God or somethin'??? e.g.: 1) Adobe is proprietary close source software, if i can remove it from my system and replace it with an open source alternative that i know it's being actively developed and maintained, i'll do that in the blink of an eye 2) if for whatever task i can have one program installed on my system instead of two, i'll gladly go for the first option 3) I trust mozilla more than others, so if i can use firefox for a task instead of something else i'll go for that instantly I'll stop here, feel free to add some more yourself. The point is, there ARE reasons, you'd just have to spend a few minutes and THINK before posting!