#5 - Bartlesville, OK
Oh Lord!
Before my current job, I worked for Phillips Petroleum (and then ConocoPhillips following the merger), and B'Ville was Phillips' corporate HQ. I visited once, and while it's a nice town, its definitely an "oil town". Since the merger, it was my understanding that the town was definitely slowing down, because most of the corporate types moved to either Houston (the new HQ...Conoco's old one) or nearby Ponca City, where Conoco had a major presence.
The people I worked with in LA always dreaded being told that their job was being moved to B'Ville.