OSDir Application Screenshots
Chris writes "Did you know that OSDir now does frequently updated screenshots of open source apps, including Evolution 2.0, KDE 3.3, Gnome 2.8, Enlightenment DR 16.7.1, Thunderbird 0.8, and YaST? Have a look!" These screenshot tours are a great way to see how polished (or not) a particular piece of software is getting, especially when you absolutely have to know what every menu item holds.
While screenshots make for nice eyecandy, they tell you very little about an application.
Anyone can put together a fancy UI using a GUI builder, but the functionality behind that UI may not be in any working order.
Featurelists, buglists, and roadmap are the important items of documentation. Not screenshots.