I struggle with this one myself. I do know that the way some remains are treated in a manner I never want to be treated in. However, I personally don't mind the thought of my remains improving scientific knowledge in some way. Presumably, this is a concept that would have been totally foreign to people in early times, so that argument can't be used for them.

I think reburial with any sort of ritual is probably going to be as insulting to the 'spirit' of the person as being dug up in the first place.

Laying them to rest in a dignified manner may be the answer, but I'm a great believer in once you're dead you're dead. I don't need to have a spirit world to look forward to. Do what you want with me when I'm gone as long as it doesn't upset those I leave behind.