The Library of Congress has released the Library of Congress Recommended Format Specifications 2014-2015.
Here's an excerpt:
The creation and publication of these recommended format specifications is not intended to serve as an answer to all the questions raised in preserving and providing long-term access to creative content. They do not provide instructions for receiving this material into repositories, managing that content or undertaking the many ongoing tasks which will be necessary to maintain this content so that it may be used well into the future. Tackling each of those aspects is a project in and of itself as each form of content has a unique set of facets and nuances. These specifications provide guidance on identifying sets of formats which are not drawn so narrowly as to discourage creators from working within them, but will instead encourage creators to use them to produce works in formats which will make preserving them and making them accessible simpler. Following these specifications helps make it realistic to build, grow and save creative output for our individual and collective benefit for generations to come.