I've thought about this for many years and for me, three factors are critical:

1. Has to be in the US
2. Has to have mountains
3. Has to have a ocean close by

I found that there is only one place that truly fits the criteria and that is Hawaii. I will never be able to fulfill this dream due to other constraints so I make do with what I have and visit 2 and 3 as often as possible!

"Never underestimate the power of human stupidity" - Robert Heinlein