Saving Video Files

What is the best solution for storing DV footage? For example I could just keep them as .AVI files or convert it to DVD, then delete the AVI's?. I could possible do both and have a set of AVI's as backup and DVD's as the viewing source. But wouldn't this be a lot of DVD's? Which I'd rather not have. Also, I have to consider that one day, if I do convert then to DVD, then I will have to one day convert them from dvd to either hddvd or bluray. I guess what I'm trying to say is what is the common and best method, with the future in mind?

It's about storage space... my home movies take up in raw capture format (avi) 1.5gb for 7 mins. That means I get a whole 21 mins on a dvd.

Frankly, the tapes are an excellent source, and if kept well will outlast a dvd...