I never made the connection with Ryder trucks, that's an interesting one. It's sort of a reverse Q-tip effect, where instead of your brand being generically associated with your product, it's associated with the worst possible thing it could be used for. Few products have been so spectacularly misused as to warrant such treatment.

Anyway, my personal favorite has always been Philip Morris turning into Altria Group. I can just imagine the meeting where they came up with that one: "you know what, fuck it, let's just make up a nice sounding word."