After experimenting a bit I found that acidrip wrapped around mplayer's mencoder produced much smaller avi files for my archives. In general, I was able to use the following process top rip DVDs:

1. Put the dvd in the drive and click on “Load DVD”.
2. Choose the first title (listed by number and length in time only) that is also considerably longer than the others. Generally this was the first title. Sometimes there were multiple titles that were long. I think these were alternate resolutions. I always chose the first one and it seemed to work.
3. Under the General tab, choose the first audio language for your languages (mine is english, obviously) that was 6 channel. If no 6 channel is available, chose the first 2 channel. I don't know if there are other options – none of my DVDs had any others.
4. Set the Audio Codec to lavc.
5. Change the Audio options to acodec=ac3:abitrate=128. This produced files that were more easily playable by both xine and MPlayer. Not sure why ac3 was better supported, but it was.
6. On the video tab, set the Video Coded to lavc and the Passes to 2. Two pass encoding was required to get the audio correctly embedded into the AVI.
7. Also on the Video tab, click on the Detect button to find the optimal crop information. This isn't required but I think it helps reduce the file size.
8. Click on Queue (you'll get 4 lines in the Queue tab) and then click on Start. For some reason if I didn't Queue it up first the encoding would fail.

Some of the problems I had were with specific DVDs failing to complete correctly, like one of The Matrix DVDs. The result was that the AVI file is not indexed so you can jump around the video. Annoying, but I can live with that. Most of the DVDs I ripped worked fine. I have 73 DVDs ripped right now – not a huge archive but most of my good ones are there. I can now watch a movie on my laptop before going to bed using mythtv. When I get my diskless MiniMyth box running downstairs we'll be able to watch the archived movies on the big screen TV. I have no idea how well these ripped movies will play on there, but it will be interesting to try it out.