Often you hear designers asked where they get their inspiration for the creative designs they develop. Personally, the very first place I go is to my clients. Their favorite things, hobbies, careers and families provide much of the inspiration for me. In addition to the client, designers often say they are inspired by their travels and by the art, architecture and designs of other professionals.
I recently had the pleasure of finding inspiration right here in Chicago at the Driehaus Museum. http://www.driehausmuseum.org/ The building itself is a gem and they also feature exhibits which change periodically. Right now they have a French poster art exhibit. I can't say I would ever decorate a client's home this way, but there are always things that I pick up when I go to a place like this that provides creative input for me.