How archival is DVD-R?

[pcpacker]

I just did my first year of home video editing (seven more to go). It took me a week of doing, and about 40 gig of my 160 gig hard drive. I was hoping to make 3 copies of the movie onto dvd and delete the project to start on the next one. Here is my dilemna:

1. External drives are expensive and I have heard about too many that go bad

2. I have heard that dvd-r only have a short life expectancy even when sitting there unused in a drawer.

Any good advice would be great.