Dayton
I'm going to speak a little bit of blasphemy here on this board but quite frankly I'm bored with Oshkosh and Sun'n-fun.
I'm a little burned out though after chasing the Aerobatic champions around the country for quite a while, I've probably seen something like 200 airshows. From Reading to Farmville to Oshkosh to Reno to Titusville to Lakeland to Andrews, etc, etc.
Dayton is a little different because it is a Military Hardware Sales event. I went one year and there were Saudi shieks getting up close and personal with Cobras, F-16's, etc. Very interesting. A mini Farnborough/Paris show - Dayton has always been a favorite in my heart.
So if you've been to a bunch of shows, Dayton. If you've never been to an Oshkosh - well you gotta go just once!