Best format for long-term disk storage

I have about 50 hours of DV that I would like to store on hard drives, for use in making DVDs. The native AVI files, at 13GB/hr, are too large, but I would like to preserve DVD quality. My thought was to keep it in MPEG-2 format, so I used ULEAD VideoStudio to import it, but it defaults to frame-based, creating interlacing artifacts when I create DVDs. At a minimum, I want to minimize the processing so that as little information in the original as possible is lost. I would be happy to have up to 4.5 GB per hour, since then I could put each hour on its own DVD for backup. 1. Is the right format MPEG-2 interlaced (bottom field order)? 2. What bitrate is enough to insure that the quality will not be an issue? (Ulead VS defaults to variable 6000 and audio 256k but why not increase these to 8000 and 384?). 3. What is the best reasonably-priced program to do the encoding?

I'd use CCE or TMPEG to convert the DV avi to mpeg2. There's a guide on Doom9's site on how to create DVD mpeg2 with both programs, AFAIK. To get a grip on the sound you'll need to save the DV files as type 2 first (with PCM audio) - then use avisynth to open the video in the encoder program OR save the type 2 DV with a VFW compatible codec (like the Panasonic or Mainconcept) in the first place.

Inconclusive results of a test 

Yea I'm not surprised...I have a 1.4 Gig Athlon and it takes me 4-5 hours to convert an hour of DV video to mpeg-2 using tmpeg or the built in encoder in Adobe Premiere 6.5

Correction 

TMEPG