I needed to batch-process PDFs to convert them into JPGs, and as usual, several solutions were found:

• ImageMagick (requires GhostScript for PDFs)
• PDFCreator

(I found several other solutions but I couldn't be sure they would work under Windows 7.) 

I'm sure Adobe Acrobat can do the job, but I don't have that hefty piece of software, and wherever possible I like to use open-source solutions.

I downloaded the binary for ImageMagick and installed it without issues (on Windows 7).  I was excited to use ImageMagick, but unfortunately I couldn't get it to find GhostScript when I went to use the convert -density 300 *.pdf *.jpg command.

Then when I installed PDFCreator, for some reason it didn't install GhostScript the first time around.  So I uninstalled and reinstalled, and this time it worked like a charm.  I enabled Auto-save and selected JPG under File Type in Options > Auto-save.  Now all I had to do was select all the PDFs I wanted to convert, and they would get auto-saved where I specified in the Auto-save options.