As a team we have had lots of discussions around OpenXML of late. But I think Dave summarised the importance of OpenXML perfectly today:
"OpenXML was the primary success of the POC I did with <ISV NAME REMOVED> last year. Every other piece of the puzzle could have been achieved with some other piece of technology, MS or not, but without the ability to create and manipulate Office documents so easily on the server none of it would have been possible. Incredibly simple technology, but yet so powerful."
Treat yourself - set aside 20mins to learn a little bit more about OpenXML this week - you will not be disappointed.