Chicago is a pretty dog-friendly city. I've lived in several neighborhoods that are all great for long walks, etc. For me, I'd avoid overly congested areas, like downtown/ loop. Lakeview has several dog parks, Lincoln Park is great because of the park and access to the Lakefront path as well as a couple of dog parks. I currently live in the Roscoe Village / North Center area and I love it here. There isn't a dog park near me, but there are endless quiet streets and places to walk--there is even a dog friendly bar around the corner from me! Let me know if you have questions about a specific neighborhood--all in all, this is the perfect place for dog lovers.