My husband and I just returned this last weekend and we stayed at the Sheraton Hotel and Towers. I loved it as it was close to Navy Pier and within walking distance to Michigan Ave.
Look online and you could purchase a package that includes many of the attractions you mentioned. I think it is called The Chicago Go Card(?). If you go, I would recommend the Hancock Observatory, the Field Museum, the aquarium, and if your children are young (mine are 2 and 7) we went to the
lego store, the american girl store, the hershey store and if you want to have the most excellent dessert ever - Grand Luxe Cafe.

They make it fresh for you and they are to die for! (They also have the best margaritas too!) Hope that helps. We are planning to go back with the kids in June.
BEWARE! Parking is outrageous

($42.00 for valet which lets you come and go, but then you have to pay at your destination).

We parked our car at the holtel and walked or took a cab.