The 10 Gadgets That Changed the World (from Wired News)
Wired, I think, has this one right. It's not simply enough to be the first one out there. To have an effect on history, you've got to be out there AND people have to actually paying attention to you. (There were plenty of PCs that had GUIs before the Apple Macintosh, for example, but you couldn't buy them for anything like a reasonable price.) Once a critical mass of people adopt the technology, then the culture changes to incorporate it.
Looking at this list, I can see that I owned two of those gadgets ... not just something from the genre, but the *actual* model listed. Not in the year cited, of course, but still, we did own those items. One's even in my basement.
Bonus points on the homework if you can guess which two I owned.
Gotta go now. Top Chef is on in five minutes.