Jean Pierre pointed out a fabulous little extension for Firefox 3 on OSX:

The firefox-mac-pdf extension embeds PDF files right in the browser, so you don't have to download them, open them with Preview.app and remove the file off your desktop afterwards. It works much like Acrobat, except it uses OSX's built-in PDFkit.

That's definitely an extension I'd like to see on AMO.

Read more…