Are you sure you didn't look here ? : http://en.wikipedia.org/wiki/%C3%8Ele-de-France_(region)
It seems pretty complete to me. The most important cities (to me) are Paris and Versailles, but there are many others like Neuilly-sur-Seine, Clichy, and so on.
It's important because France is a very centralized country, so all the politic, economical power is located there, and, as for education, all the best schools, colleges and institutions are there as well.
There is some agriculture there, but it's not exactly its forte, and this region isn't famous for any product in particular (not that I know of, at least).
So, in my opinion, its main specialty is its historical heritage.