I may as well add my 2 cents worth. I live in the Southern US where we have delightful winters and unbearably hot and humid summers. America is massive, I believe my state of Louisiana is as large as the UK. Yes, we travel a lot from state to state on vacation ... I've been all over this country and there are amazingly different cultures, landscapes, etc.
I've read the other comments and would totally agree about Austin, TX. It's a big city, has traffic congestion, but offsetting that is the great university, the live music scene, and the absolutely laid back atmosphere. Summers might get pretty hot but winter should be mild.
If you prefer mountains, there's a smaller city in the East called Asheville, North Carolina, that has a nice lively live music scene, a very tolerant culture (right in the city), some great restaurants, microbreweries, etc. Also they are into organic locally grown food, have a fabulous farmer's market. It has a 4 season climate.
Northern California is great, especially San Francisco Bay area. International culture, live music, beautiful scenery. Very high cost of living right in the city but more affordable in the surrounding area.
Also love Southern Cali, especially the San Diego area; lovely weather, the beaches and ocean are to die for, again high cost of living but better than L.A. L.A. has everything but traffic and freeways are a nightmare and rush hour(s) are long.
Nashville, Tennessee is also a great place, 4 seasons, large enough for lively live music scene. Of course it is the country music capital of the US. Great central US location close to lots of beautiful scenery.
Love New York City. Manhattan extremely expensive to live in, more affordable in outer boroughs. I would love to live there for a few years and experience everything. There you just mostly park the car, ride the bus or take a taxi or walk, as long as you're in Manhattan.
There's basically a trade off as far as weather --- the north has appalling cold winters and lots of snow and ice, but especially in the midwest & north, the summers can be equally as hot as the winters are cold. The south has great sunny mild winters, though we do get down to freezing and below, usually not for more than a few days at a time. Summers are often unbearably hot.
I'd want to live at or near one coast or the other, in a large city, for more opportunity for work, various cultures, acceptance, etc.
If you don't have a job with health insurance, you're in a bind over here. Health care costs become more outrageous every year. I don't know how to compare ours with Europe, Canada or anywhere else.
Sounds like a good idea to do some traveling while you're still young, staying long enough in each place to get a true feel for what it's like to live there. The longer you wait, the less likely you will be to find that new place where you feel at home.
Sandy
I know a place ....