Overall, I would recommend British Airways given the Chicago lounge experience and their robust in flight product. pAs you will recall, BA invented the lie flate business class seat and in its new form (New Club World) it is even better. To ensure that you have new club world try to book on a 747, which currently runs on two of the three flights a day. You should also request an upper deck seat to sit on the second level if possible.

Before departure, make sure to spend plenty of time in the lounge where you will be able to order dinner, have a glass or many glasses of wine, champagne, cocktails, etc. The food is very good.

If for some reason, you cant fly BA, I would go for Virgin, who has a nice upper class product. The benefit with VS is that they have a bar on the plane and fun service. Last I saw at ORD, they are flying an airbus A-340. Looks relatively new.