Up until today, I'd been using Paparazzi for full page (scrolling) screen caps. Although it's a great program, if there are any database-driven elements, it can't capture the page. So in comes Pearl Crescent Page Saver to save my day.
It's FREE and the best part of it is that, instead of opening a separate pop-up window to capture the screen, PCPS adds a simple little camera icon to your toolbar. Clicking it allows you to capture a selected part of the screen or the whole page. It's the first program I've found for OS X that works as well and as simply as Screen Catcher (which is fantastic, but doesn't work in OS X). Huzzah!
Here's the proof – all I did was click the camera and create a file name.
Pearl Crescent Page Saver
(A gazillion thanks to IONCANNON for making my life way easier. Thank you!)