Mister E Man of I.T.

What software do you use for PDFs?

I'll make this a little simpler and include both reading and writing PDFs.

Firstly, reading PDFs - generally this still is best accomplished using Adobe's Acrobat Reader which is freely downloadable here, other variants that I've used include NitroPDF Reader and Foxit Reader.

To create basic PDFs, i.e. print-to-PDF functionality, I like CutePDF and PrimoPDF (PrimoPDF is linked with the NitroPDF company) but nowadays you can also save to PDF from more up-to-date Office products like MS Office 2010, LibreOffice, or OpenOffice.

For creating and editing PDFs, Adobe's Acrobat Writer tends to be out of the reach of most users in terms of costs, so here I have happily been using NitroPDF Professional which for a reasonable cost provides a good feature set - I've personally made a lot of use of modifying the contents of editable PDFs as well as using watermark templates for paper-based forms (and printing to them from MS Excel).
 
So there you go, plenty of options...