I'll be visiting every program I was/will be accepted to. This is on the advice of several of my professors at a Top-5 institution. I was told that regardless of whether you enroll, you'll meet more of your sociological contemporaries (people that will be graduating, going on the job market, and contributing to the field around the same time as you). Also, not only will it send the signal that you gave each school a full and fair consideration (which you should, regardless of where you -think- you want to be now), the schools you don't attend may be schools to which you'll be applying for positions in a few years -- apparently memories in academia are quite long. So, if you think you can spare the time, and they are offering to cover your expenses, I think it's worth it to visit each of the schools at which you've been offered a place.