Format used for saving caputured video.

I have Dartfish as well as Pinnacle Studio 9.
I am wondering what programs you guys use to capture video and what you save the files as?

It seems that obviously when I save my files as dv avi files the quality is much better to watch and to analyze on dartfish however the files are really large. For a 17 second file the size is around 65 mb and if i convert the file to wmv it is less than 5 mb. Also it seems with dartfish that I dont have a choice how to capture video but rather after it is captured I can convert it. What is the point in this? It is still taking up more memory on my computer?
With Studio 9 I can pick either dv avi or mpeg, and although mpeg is smaller it is pretty crappy compared to the other format… what gives?

Im just curious as to what you guys do when capturing video and saving it to you PC, im still pretty new to this?

thanx!

From DV-AVI, we convert to mpeg1 or mpeg2. The latter, of course, requires a compatible decoder card. The quality is quite good, though file size is larger than .wmv conversion.