San Francisco--I love that place every time I go. I could see living there as difficult, but 3-4 days at a time are simply fantastic.
Crested Butte, CO--It's changing. The word is out about how awesome it is. But it still has a small ski-town feel. We go every summer and winter.
NYC--only been twice, and both were for work. But I found it fascinating. I can see why people that live there get hooked.
Charleston, SC--I lived the first 6 years of my life here and my dad was from SC, so we visited 2x per year up until I went to college. I love the town, and I've spent many weeks at Kiawah over the years. I'll lump Kiawah in with Charleston.
Driftwood, TX--I was going to put Austin, as I've lived the area since I started at UT in 1995 and had no desire to find a job anywhere else. But there is a reason we moved out to Driftwood 10 years ago. I'm a bit of a homebody, and I love where I live. I'm next to nothing, but 10-15 min from anything I want. It's dark, and it's quiet. And unfortunately everyone is figuring this out.
I haven't spent enough time in Seattle to put it on the list, but the very short time I've spent there makes me think it would make my list if I could spend some time in the city.