The big problem with storing data is not simply that the media can go bad; the data formats may be unreadable in the future due to lack of machinery or software. If you keep refreshing your backups (and transferring them to new media formats), you have a way to deal with the first part of the problem. The second issue also requires some vigilance.
Pure geeks tend to keep their data in simple ASCII (*.txt file format). Using this format means a large variety of operating systems and applications can pick it up. For simple (non-relational) databases, comma-delimited or tab-delimited formats often work (CSV, or comma-separated values; there is also tab-separated values, or TSV.) The old dBase format (.dbf; often called xBase format) still has numerous users. Probably the most popular use for these is simply for shifting data among proprietary formats.
But your problem is to find a format that will preserve as much of your data as possible. Those *.txt files will not save the fancy formatting (italic, bold, etc.) you worked so hard to put into your document. If the danger to future access to the data is having it in a proprietary format (such as .doc or .xls), what widely-used, non-proprietary formats are there that go beyond the simple?
You have named an important one, OpenDocument Format (ODF). It is not yet widely used, but its benefits are obvious. It can be freely used by proprietary and non-proprietary software alike. Its basis in XML looks forward to the Internet, rather than back to mere desktop computing (although you can use it on your desktop if you have the appropriate software, such as KOffice (Linux, and maybe eventually Windows) or OpenOffice (Linux and Windows). Depending on how fancy you are with your documents, these applications should be able to pick up your present documents in their original format (presumably .doc, .xls, etc.) and translate them into ODF.
If you are serious about archiving, you can add ODF to your present archive methods. If you would like more convenience, you can create your documents in ODF to begin with.
One caution: ODF is a standard. Implementations of this standard are up to other parties, such as KOffice or OpenOffice. The full standard may not be implemented, and implementations can vary among products. Translating complex documents from one standard to another may not be picture-perfect.
ODF is a good choice for the future. There are a lot of people and companies (everybody but Microsoft) looking for easy document interchange among operating systems and applications.
This was first published in November 2006