I like the Full DVD so I can make quality AVI if I want to or I can watch it in full quality on my widescreen TV. I much prefer the Full DVD given the one choice.
and to celebrate our diversity…I prefer a good quality rip from DVD to AVI, defining "good quality" as (1) the same resolution as the DVD, and (2) minimal or no compression of the video. These will play on many new DVD players and give the same result as playing the original DVD. (I have a Philips DVD player that will play .avi files from a DVD, or from a drive plugged in to the player's USB port.) These .avi rips are also easier/faster to download, because they're usually about 1.5 GB for a full-length film, instead of 4 GB.
But...it's important that the DVD rip be done with quality of the end-product in mind. I don't have the software to rip DVD's myself, so I'm not going to criticize anyone who has ripped a DVD and seeded it here. But I would suggest that people "rip for quality."