Preserving negatives (photographic film)

I have collected a huge sheaf of negatives over the years, and my collection can only grow because I’m one of those low-tech, non-digital camera types.

Now, I know that you should keep negatives in an atmosphere free of moisture and away from the sunlight, but besides that what can I do to ensure longevity? If I leave them in those plastic wraps they come back from the developers in, is that safe? Or should is there a preferable storage procedure akin to stamp-books for philatelists?

Information, please. Thank you kindly.

Check out this thread from Should answer your question.