PDFCreator
 

This is what I use for making the drawing PDF's:

http://www.pdfforge.org/products/pdfcreator

For drawings, it is about as efficient as the Adobe products.

However, for Word documents, Adobe makes a much smaller file than PDFCreator. Because PDFCreator only emulates a printer, it doesn't recognize text as individual characters, but only as an image.

I like PDF creator myself.

I use Open Office (Office suite) which output PDF format.