Documents (presentations and spreadsheets, mostly) that I'm strictly using myself (not sharing with others) I preferentially create in iWork.Am curious how you divide your work between Office and iWork? What makes you use one over the other for some files? Seems like a headache to manage two office suites.
Things I receive from others or that I create but know need to be shared, I tend to use the Microsoft products.
It's not too much trouble at all since iWork does a good job of converting to MS Office documents or PDFs when necessary.