Apple - How to take a full page screenshot in Mac OS Safari?
No plugins or anything needed - latest Safari (7, not sure from which version this works) can save to PDF. File -> Export as PDF... and you get entire page, images and all. And it's a lovely hi-res PDF.
Paparazzi! is great for full page screenshots. It is not a Safari Extension, yet it has a very nice feature that enables you to launch it from Safari.
Type paparazzi: in the address bar before the URL, it will launch the application with specified URL. Here is the list of URL format that Paparazzi! uses: http://derailer.org/paparazzi/urlformat
Maybe Don't give http://awesomescreenshot.com/ a try, see disclaimer below. There are better options available, see other answers to this question. Awesome Screenshot is a browser plugin that can capture
- the full site
- the visible part or
- a selection of the site.
It also allows for basic annotation of the screenshot as well as downloading it or saving it on the web for access by URL. Available as extension to Safari, Firefox and Chrome.
DISCLAIMER: there are strong indications that Awesome Screenshot sends information about your browser history to third party servers. I would not recommend this after all. It also has a history of integrating adware in it's extension and then apologizing for it afterwards.