So I made it to "the event" last night, and it was truly an Obamapalooza. I don't know how many people, but it was a nothing but people. the link below is an aerial map of the area. Obama was in Grant Park, which was at least 140,000 people. I was in the park just above it which was completely packed by the time it started. So was Jackson Blvd out to Columbus Dr. We had a great spot right on Jackson in the front pretty close to the jumbtron.
Map
This is the announcement when the California poles came in, which was when he was ultimately announced the next president.