A few screen-shots and a description is nice, but nothing sells like a good video. Are there any sites that feature video to get an idea what an App might be nice? Youtube is obvious, but if you are just browsing and not specific on the app you are looking for, it's hard to find a collection of stuff all in one place.
I use AppAdvice, then once I see an app I'm interested in, THEN I go to YouTube, or directly to the developers site. There is either usually an amatuer review on Youtube, or many developers have a video of their app on their site.