Cheapest way to backup data

[eric-yrHdaQSNc4gdnm+yROfE0A at public.gmane.org (Eric Chadbourne)]

"...I have about 100gig of data..."

I have about 3x that.  Mostly music and movies.  Somebody on this list 
talked about having 3 copies of everything and that made sense to me. 
So for my personal data I do the following.

1.  Working copy.  Local drive.
2.  Fast backup.  External USB drive.  (Not that fast with hundreds of 
gigs.)
3.  Slow backup.  DVD+R.  (Really freakin' slow.  But I only need this 
if two drives fail.)

I switch operating systems and do fresh installs all the time and 
haven't lost data in a quite a while.  Super cheap, easy to understand 
and works.  Of course if my house explodes due to a gas leak I'm SOL.  :-)

- Eric C