I use slingbox to quality control a second cable headend channels. I am not sure how many users do the same but with the video there are times when I need to capture the screen or the stream for verification purposes of an existing problem.

I have seen many comments on different programs for screen capture and seems snagit is very popular. However I have found that Camtasia really works well. It is not cheap, but the functions and capabilties of it, makes it my number one choice for capturing the streaming video.