I chose to come to Chicago. It has its ups and downs (let's face it, everyone dislikes their school at some point). There is no shortage of sites, but the same is true for many of the DO schools in larger cities (NYCOM, NSU, PCOM, UMDNJ, etc). Some of the cites here are awful, and others are quite good. We do our "core rotations" in Southern Illinois (one hour south of the city without traffic). Be prepared to travel or forget living in the city at all. The first two years you'll live in Downers Grove (~45 minutes from the city) and surrounding areas. Again, not exactly the "city life" but you have your choice your 3rd and 4th years, as I mentioned.
If you know what you want to go into, I would recommend going to the school that has the residency you want. DOs like to pick from within their affiliated institutions.
As far as cities go, I love L.A. and Chicago. L.A. and California in general, has things that Chicago can't compare to (beaches, mountains, mexico). You could go to Tijuana for the weekend, wine country, or snowboarding in the mountains with just a short drive. Chicago has great museums, sports, and food. Both cities have great night life.
Tough decision, but thought you should weigh all the options before choosing.