PDF Download 0.9.3.1
PDF Download is a Firefox extension that solves the problems everyone has about handling PDF files with Firefox. PDF Download is not a PDF plugin: you still need to have installed the Adobe or the FoxIt PDF plugin if you want to open a PDF inside Firefox.
This extension, every time you click on a link, checks if the target is a pdf file (checking the MIME type) and in this case let you choose what you want to do (open pdf file inside or outside Firefox, download it to the filesystem or view it as HTML).
Available in almost 30 languages!
Download: PDF Download 0.9.3.1