To date, I've been keeping them in envelopes stored in a cardboard box in my attic. Amazing enough, most of the negatives survived a major fire we had about 5 years ago, although almost all my B&W newspaper prints were wiped out. Incidentally, my hard rives which were sitting on my desk all survived, despite the only potation being a tarp the fire fighters put over them.
A buddy of mine in South Africa is writing book about some of the fighting that went on after the main 1994 elections, and asked me to contribute some photos. It took about a week of searching through the attic to find the box of negatives, then I had to dig out my negative scanner, then a 10 year old iMac because my modern machine wouldn't run the negative scanner, then spend 20 minutes per image to scan them in high-res (I'm going to punch the next kid who tells me film is the only true photo medium). Scanning work you did 18 to 20 years ago is a very strange thing, the images come up like they were shot yesterday, and the ability to get details in negatives you thought (in the pre and early digital days) were un-printable is wild, so a lot of it is like new material.