Formats more likely to be accessible in the future are:
Consider migrating your data into a format with the above characteristics, in addition to keeping a copy in the original software format.
Examples of preferred format choices:
Library of Congress' recommended file formats.
Directory structure naming
When organizing files, directory top-level folder should include the project title, unique identifier, and date (year). The substructure should have a clear, documented naming convention; for example, each run of an experiment, each version of a dataset, and/or each person in the group.
File naming
Use free tools to help you:
http://www.bulkrenameutility.co.uk
http://www.powersurgepub.com/products/psrenamer.html
File naming conventions for specific disciplines