All the states I've ever been to. :) All of the states besides CA and NV were visited in one summer when I joined drum corps, which is marching band minus the woodwinds and plus steroids. This requires the people who join to go out and work on one field show for about 14 hours a day, every day, for the entire summer, with the occasional free day thrown in here or there. So understandably, I didn't see much of the states besides what passed by the charter bus windows, and what surrounded the high/middle schools we stayed at, but I was there nonetheless.
Favorites: California, Georgia, Pennsylvania, Ohio, New York.
Least Favorites: Kansas, Texas, Louisiana, Mississippi, Indiana, San Jose, and Houston (which were so terrible they gets to be separate from their states).
Nicest school: The one in Houston, Texas. Too bad they kept the air conditioning on full blast and made us sick every time we wanted to come inside.
Worst school: The one in Mississippi. We had to ride a bus to this crap field because they wouldn't let us use theirs. -_-
This is based on the weather, along with the quality of the fields and the taste of the water, because when you're on tour that's all that matters.