I would argue Foxit Reader 2.0 is the best alternative to Adobe Reader for Windows. Unlike the bloated Adobe product; Foxit Reader 2.0 is light on system resources and opens PDF docs extremely faster than adobe. Foxit Reader 2.0 also includes free add-ons, no lengthy splash screens, has an intuitive streamline interface, and is under 2MB download size.
Mysicgeek’s Tech Lingo: PDF (Portable Document Format) This format was originally created by Adobe Systems in 1993. A PDF file is a digital version of a paper document.