I'm totally going to answer Melisa's question first. Mostly because she took the time to ask and it's an easy one for me to answer.
I think my first choice would be Boston. I've never lived there, but did spend quite a bit of time there when I was just out of college for my first job. I love the architecture; I could walk the streets for hours just looking at the brownstone buildings and cobblestone streets. I never understood history quite like I did when I was there. I love the seasons there, even the cold! I love the diversity-the intellectual, the scientific, the cosmopolitan, the suburban. I have a soft-spot for the Atlantic ocean and love the east coast.
If you could live somewhere else and it HAD to be a city in which you've never resided before, where would it be?
If the time spent there would disqualify me from Boston then I would probably choose Charleston for many of the same reasons. The beaches there feel like home to me even though I'm a west coast girl by birth. I'm not sure you could learn everything there is to learn about either one of these east coast cities. I learn something new every time I go there.
If you further qualified your question to only foreign cities then I'd probably be stumped. I love London and have spent enough time there to feel quite comfortable. I love the history and tradition of the Royal family; it's fascinating to me. I could live there but I would hate to limit myself. There are several other European cities that are definitely on my Bucket List, and I would love to go back to Singapore someday.
But, really Melisa? I want to live in Denver. I've never actually lived in Denver proper, so it qualifies. There are beautiful old streets that have unbelievable homes with giant trees and a view of the most beautiful mountains on the planet. There are sports teams and the symphony, and museums, and miles and miles of trails for biking/walking. It's where my heart is.