I guess that my suggestion of India requires a little more argument:
All the places listed above, with the exception of Slippery Rock, are good, but they are all places you can get too pretty quickly and explore in a couple of weeks. Plus you can go to many of those places with your wife and kids in the future. However India is hard to get to and more adventurous than most people care to take on, so it will likely be harder to get to for you later in life. Plus Central Europe, while very cool, is a very similar culture to the US. India is just a different world and will expand your horizons as much as any place on earth can.