Also, Austin is one of the few major cities where you can consistently drive at 40-50 mph. Because it's sprawled out and only has one interstate, you can enjoy both walking around downtown and driving to and fro (now driving down or up 35 is a nightmare). In NYC, forget about it. In San Francisco, driving is only tolerable before 7 AM or after 7 PM. Except for Nob Hill, I never drove faster than 25 mph in SF.
If you want to party hard and enjoy youth, San Francisco would be ideal, but you have to be freakin' rich or live like the residents of Asiatown: cramped into a small space with tons of roommates. Austin and Portland are the next best bets.