Earlier quoted context omitted.
That definition assumes that there is such a thing as an "app worth buying a phone for" that holds for a majority of people . That will always vary by person. I've listed killer apps for Android for me; as I said, I can make no claims about killer apps for everyone, nor can you, or for that matter, Gruber. So I guess the term is kind of silly in the first place when applied to third-party mobile app offerings, no?
The iPhone had a killer app in the full web(minus flash) web browser. No other phone at the time had a web browser anywhere near as good as mobile safari is. That and google maps and mail made a compelling case to buy the phone.
The N95 was out for a year earlier and had a mobile webkit browser and 3G. That said, the 2G iPhone had a larger screen.