Where are the best places to live in the U.S.?

I'm a southern girl (a native north-Georgian) and I love the spring and fall here in the south (the weather is wonderful and the flowers/foliage are beautiful) but the horribly hot and humid summers and incredibly cold winters are becoming too much to bear. I'm planning on moving once I finish school, but I'd like to live somewhere in the U.S. that is a little more temperate. Also, somewhere very versatile in regards to career and family life would be great. Somewhere business could be pursued and there's always something to do without having to live in the middle of a city similiar to Atlanta and also somewhere teaching or a medical career could be pursued along with being a safe, healthy place for children without having to live in the middle of nowhere. Any ideas?