Windows only: We've covered a variety of tools for converting PDF files, but if you need to bulk convert a pile of them Zilla PDF to TXT Converter gets the job done quickly.
If you only need to extract the text from a document or two some of the solutions we've covered should more than suffice, such as using PDF-to-Word-Converter or the built-in converter in the most recent Office 2007 service pack.
If you have lots of PDF files you need to extract text from, Zilla PDF to TXT Converter makes batch extraction a breeze. The freeware verison is limited, as the name would suggest, to converting PDF files to plain text. You can specify the page range and whether or not to acknowledge page breaks on a file by file basis. The commercial version, PDFZilla, is $US29.99 and offers batch conversion of PDF to Word, RTF, TXT, and HTML among others formats. Zilla PDF to TXT Converter is freeware, Windows only.