Star Trek's replicators uses Energy->Matter conversion to create items, then Matter->Energy conversion to reclaim them. Much cleaner than compost.
Replicators would have been my choice too
, but if limited to reasonable uses of current technology, I want centralized, reasonably priced repositories of all the media ever published/recorded/filmed. No more wondering if something is available electronically yet, and which store would I need to purchase it in. Hopefully that would eliminate much of the motivation for piracy, adequately compensate content creators and publishers, and stop the waste that accompanies overly large print runs and transporting media by truck to retail stores.