Most interesting in the comments on this blurb, a similar experience to my managing bibliographic data between Word users (Ryan and Christy) and Jim's WordPerfect.
You must be using extremely simple documents... basically plain text. My supervisor and his other grad students use different versions of Word (I'm not sure which one), but all the the figure positions, get screwed up, equations get put everywhere, and it's a general mess. I manage to maintain compatibily with both of those guys by not using Word but OpenOffice instead. It's actually this lack of compatibility between Word versions that got one of the other grad students to switch to OpenOffice, which was better at handling different versions of Word documents than Word itself.