Here is another possible idea: having an icon that can stand on its own, as well as a wordmark that can stand on its own. This way, you potentially have 3 logos in one! (The icon, the words and the 2 of them together as one.)
The icon would work great as patch, letterhead, etc. for when the entire logo isn't as applicable. And then wordmark could also be used without the icon for things such as titles, web banners, etc.
(This comment references Entry #17)