My favorite place on the planet that I've ever been to is Hawaii, but it's too expensive to live there, so wouldn't recommend it for your situation. But I bring it up, because you want to compare the cost of living to where you are now -- you need to know if it's going up or down.
Second choice is San Diego area (by which I explicitly include as far North as Encinitas) -- cost of living is not that different from DC, so would be a serious consideration for me, were I in your shoes.
Third choice would be the bay area (San Francisco/Berkeley/Menlo Park/etc.). Sister already lives there, so that's a plus. For me. Heck, might be for you, too, who knows.
Me, personally, I'd have to travel around a bit, first. I have really bad allergies, and don't know if the constant wind from off the ocean would be conducive or destructive to my symptoms. My allergist explicitly told me that I need to move to the desert, so I'd have to try that, too. None of this affects you, but since you are in a position to do so, I still think the conclusion applies -- move around the country a bit, try some places you like. I'd miss access to the big city if I moved away from anywhere near a big city.
PS My favorite big city is NYC.
PPS Most of the hottest girls I've met are from Texas. I forget if you're married/straight.