I used to use md exclusively to tape so I have quite a few (quite a few to as far as I'm concerned) shows on md. I just bought an md deck with optical out. I plan on transferring all the good stuff on md to cdr via my standalone burner. I won't get rid of the md masters, as I feel it makes for a good backup.
If you think you'll never use md again...shoot them over to DAT or cdr and get rid of them all. I plan on still using my md for mixes or for putting studio stuff I have to md for use in my portable. I figure it's always nice to have the ease of the portable for taking my music with me, and I don't worry if I lose an md here or there. I would be p.o.'ed if I lost an album though.
To answer you question...I'd say get your md stuff digitally onto cdr in SHN format. You never know when a tape might break. I think md is the more reliable archive format as far as media stability goes. I base this soley on my personal experience...not hard data.