Well...it certainly isn't the cheap cost of living up here, thats for sure.
And it isn't family, since most of mine lives in Florida. Whenever I go there to visit my dad, I'm absolutely blown away by the hospitality. I once drove him up here from down there, and we both noticed that literally every time we stopped, the farther north we got, people got more and more rude. By the time we got to DC I was wondering if I should have packed heat.
Maybe a coincidence, I guess I'd buy that- but it was very apparent.
I guess that for me it's the diversity- we're close to the shore, close to heavily wooded areas, close to Gillete Stadium and Fenway (yes that does count to me).
We have considered moving north, northern New Hampshire has always been a favorite vacation spot of ours- but the job market up there is not even close to what I make down here.
I do like it down South, but I couldnt stand the heat all year round. And the bugs...some of the spiders I saw in Florida stole my shaving kit, and hijacked the car...
I guess I'm just a native New Englander, and this is where I find a happy medium.
You can say anything foolish to a dog, and that dog will still give you a look that says, "WOW!! What a great idea!! I never would have thought of that!!"

Some people are born on third base, then spend the rest of their lives thinking they hit a triple.