I just finished recommending this software to Trevor who was complaining about Acrobat Reader being big and slow, and I realized I should mention it here too.
Foxit Reader is a free, lightweight PDF reader for Windows and Linux. It comes in somewhere around the 4MB mark on disk once installed (compared to Acrobat Reader’s 87MB), and the copy I have running right now with its own 90-page, user manual open has a 10MB working set in RAM (6MB private). It starts in a second and renders and prints PDFs very well (unlike, say, xpdf). Until version 2.0 it didn’t have a browser plugin, but I consider that a feature — I want PDFs to open in their own program. (Apparently 2.0 does include a plugin, although there’s a bit of a bug in the installer that requires some extra steps to get it to work with Firefox.)
They also offer a Pro Pack ($39) which offers PDF annotation without a watermark and a “Save as text” option.
And they don’t stop at reading PDFs — if you’re the sort that needs Acrobat instead of just Reader, there’s also PDF Creator ($35), which provides a virtual printer that lets you print from anything into a PDF file, and PDF Editor ($99) which lets you modify PDF files directly. I don’t use any of those although Creator is tempting now that I’m reading about it.
But Reader is their shining star. PDFs are so much less hassle when they’re fast.