Thanks for all of your input.  Interesting differences.  I have been rendering uncompressed frames as I will be editing them and compressing for final on DVD.  

If I weren't post working the frames I might be tempted to use a lossless codec but as stated in the discussion, stopping a codec render means starting the whole thing over.  Been there, done that.

I always remember the time I recorded an mp3 off my sound card and saved it as an mp3.  By doing this I had taken away so much sound info that it sounded like a speaker in a tin can.   Original mp3 had 90% compression and then copied and lost 90% more.  Multiple compressions kill!! 

Thanks again for your ideas.  I was going to render too large.