Public transportation. Since I can’t drive I need it. Even if I worked at home I would find it depressing not to be able to get around (I’ve been through that before).
Library is also important since I read a lot and get most of my books and all of my movies and television shows from the library, but it wouldn’t be a dealbreaker. Most cities with good public transportation would have good libraries anyway so it’s kind of a moot point.
Public transportation and real live theatre. Which explains why I am where I am.
I want to see mountains or ocean – preferably both (a person can dream). Cities, tightly built suburban areas, gated communities and rolling prairies are all deal breakers.
Malienation, you should check out the Puget Sound area. Seattle (King County) has, hands down, the best library system of anywhere I’ve lived – including the desert southwest city where I live now, unfortunately. Not bad enough to be a deal breaker, but a big disappointment.