Just got back from visiting my sister this weekend. I always, and I mean always take my bike with me. Did a nice 26 mile ride downtown on Saturday on the fixed gear. So many bike lanes and bikes on the streets that it is very comforting. There are some really nice rides like the Lakefront Path that runs between the city and the lake. No cars, just runners, walkers, bladers, cyclists, etc. Runs all the way to Indiana I believe. Take a good U lock with you and it should be alright if you are not in a stabby part of town. Honestly, there are so many people there that theft in the middle of the day with bolt cutters/portable cutter is not really going to be likely I don't think.