Today I recieved an e-mail from the Swedish Standards Institute, SIS, containing the proposal for the Office Open XML as an ISO standard (ISO/IEC DIS 29500). Office Open XML is today an ECMA standard, TC-45, and ECMA has submitted the standard to the ISO fast-track process Office Open XML. The fast-track means that it can be an international standard by this August, read more on the fast-track process in this post by Brian Jones.
I'm definitely going to second to the proposal.
I think it's really positive that we might get an open ISO standard for document formats. It will not only open up a lot of opportunities for software developers - better support on multiple platforms (I'd like to see Google Docs & Spreadsheets supporting it), it will also "force" software developers (read Microsoft) to commit to the format and not change it for every other version of Microsoft Office (unless they abandon their "own" standard).