I’ve been playing with our xbox thanks to VirtualDub. This program runs on Windows platforms and it is very light. It needs only around 1Mb of hard drive and doesn’t add that nasty lag. Moreover, it was very easy to configure, although having sound took a bit more time.
VirtualDub is specially designed for fast linear operations over video and includes a lot of different filters. I haven’t tried it much to take captures, but I managed to capture a short video very easily, though it occupies a lot of space. Now I want to learn more about, filtering, compressing and general video processing 
VirtualDub is the fucking best (free) program for video editing and so. Keep using it.