I love the idea of the spreadsheet!  That's far more ambitious than what I was envisioning, which was merely to list what I have, and which ones I've updated.  However, Renderosity doesn't seem to know which sets I bought at Daz and Hivewire, only my more recent purchases.  (Yeah, I'm in "what's left" mode, too, as the list of the stuff I don't have is much shorter than the list of what I do. [chuckle])

Thanks for all of the info; I'll get right on that.