Since it sounds like you're a walker, I would suggest the following:

Start at Millenneum Park and then walk south to Buckingham Fountain which will be lit at night. From the fountain, head due west down Congress to Michigan Avenue and again turn south - staying on the park side of the street.

As you walk along south Michigan you will have a good view of the buildings across the street, including the Blackstone Hotel, and the Spertus museum (all glass) which is pretty cool. Thirsty yet? Stop at Kitty O'Sheas in the Hilton for a beer. They have nice outdoor tables.

Continue down Michigan to 11th, and head into the park, where you will see a pedestrian bridge followed by an underpass under Lake Shore Drive. Admire the new buildings to the south, and from the bridge there is also an awesome view toward the north.

Once you're under Lake Shore Drive continue toward the lake, and turn slightly right passing alongside the Aquarium on the lake side (Don't head up the hill, stay on the lower walkway.)

Once you're around the aquarium continue on the lower level and you'll have the most amazing view of the skyline that exists. When you reach the Planetarium (end of the point) head to the upper level. If you're not tired you can walk back through the museum campus - now staying on the upper roadway, find the pathway between the Aquarium and the Field Museum, and then back through the pedestrian tunnel. Or, if you're tired of walking you can catch a number 146 bus:

http://www.transitchicago.com/assets...edules/146.pdf

outside the planetarium that will take you back to North Michigan Avenue.