Open source pdf editor
I have always used Open Office here and there but I have now seen that its a very good tool for editing pdfs.
With the release of the Open Office 3.x, the office tool has become better and like Firefox its made better by the addons one can add.
One of those add-ons or extension is the one to enable pdf editing and it can be found here.
Install the pdf extension using the Extension Manager menu option found under Tools.
Once that is done you open your pdf document like normal and it opens as an editable version. After finishing with editing, just export to pdf and I have no complaints with the end result.