Best places to live in the US?

My husband and I would like to relocate within the next 3 years. Currently, we live in Nashville, TN. I like here ok, but we would prefer somewhere more mountainous. I don't really want to live anywhere extremely hot or anywhere that has bitterly cold winters. I also like having river and lakes near by. I am originally from southeast Tennessee and like the landscape there (mountainous, rivers, lakes, etc.) Both of us would just like to have a fresh start somewhere and would like to get out of Tennessee. (We also have 2 small children). Where are some places you might consider?