I have eaten at the Italian-ish place next to the sports bar in the O'Hare Hilton (I think it's called Andiamo) several times during flight delays, etc. and have found it to be serviceable, if a bit overpriced.
It's certainly far superior to anything available in the airport proper, has a decent wine selection, and would suit the purpose of a business dinner quite well IMHO.
I exist in Chicago, but I live in New Orleans.