This is such a tough question (good thread idea btw). Looking at the bottom few teams....I'm leaning towards Utah or Dallas. The thing is, having a guy like Dirk on your team basically guarantees a playoff berth. Not to mention Josh Howard, JT, and Kidd. The problem with their team is that they play no defense, so on nights when their shots aren't falling they're done. Utah has had some early injury problems, and they don't have that guy who just puts the team on his back. Still, they've made it through the injuries so I really believe once Boozer gets back they will be even better. Bottom line, Mavs are the odd men out. Hard for me to say it, they are a quality team.
Houston are always at risk because they are so injury prone. I agree about it being between Utah and Dallas. Utah did not look that impressive against the Nets the two times they faced off, but then again they were sober (no Booz).