My girlfriend *might* be able to swing a good deal at her hotel in Schaumburg. I'll have to see how close it is to the Metra, and what the train schedules are. Plenty of restaurants and bars nearby the hotel on Golf Rd, not to mention it is only 15 minutes from ORD if we do a tour there or something. About 45-50 minutes from MDW. If we do anything at MDW, we'd need transportation.
We could also look at the Midway Hotel Center at MDW. Free shuttle service to the airport and to the Orange Line CTA station. The Orange Line is the train that takes you into downtown. About a 35-40 minute ride, if not less. Also an easy connect to the Red Line to go to a Sox game, or go up to the North side near Wrigley for restaurants and nightlife.
I am good with any weekend, although I voted for March on St. Patty's Day simply because this city has a lot of Irish heritage... St. Patty's Day is a BLAST. The weather will be much more cooperative in May or June, however.