I always leave quiet, sometimes I don't even send an email, just say goodbye to those who don't suck and split. For a big city, Portland is a tight tech community. Everywhere I work is either with someone I worked with in the past, has worked somewhere I worked in the past, or knows someone I worked with. If you piss off just one person, it could be the last person you ever get to piss off.
"You'll never work in this town again" could mean a lot.
"You'll never work in this town again" could mean a lot.