Need an in-browser PDF reader?  Sure you could go with Adobe Reader, but who wants that bloated mess?  If you want something quick, built in and simple you need to go with the Nodobe add-on for Firefox.

At this time Nodobe support 38 different file format:
Adobe PDF:pdf
Microsoft Office:doc, docx, rtf, xls, xlsx, ppt, pptx
Images:png, jpg, gif, tif, bmp, ppm, xpm
Vector Graphics:eps, ras
Text Files:txt
OpenOffice:odt, odf, ott, odg, odp, stw, sxw, std, sxd, sti, sxi, sxc
StarOffice:sda, sdd, sdw, vor
OpenDocument:otg, stp, ods, [...]

Open IT Online, an add-on for Firefox, delivers you what you want.  Well, it delivers you what you want, if you are one of those people who love all these new Online services such as Zoho’s office applications or Google Docs.  Open IT Online allows you to open your documents and images online without the need of any software to be installed.
Here are some of the extension types it can recognize and handle:

Documents (*.doc, *.rtf, *.odt, *.sxw)
Spreadsheets (*.xls, *.csv, [...]

I hate it when a PDF opens up inside of my browser, no matter which one I am using. It wastes my time and I would rather not have Adobe get it’s mitts all over my beautiful Firefox interface. Now you can either poke it back with a stick – which is not the easiest thing to do Online – or you can pick up the PDF Download extension fore Firefox. This extension allows to choose if [...]