In addition to that, the $350 gets prorated the closer you get to the end of your contract, AND alot of people feel a new worthy device might not show up in 12 months. In this case, something like a Droid 2, might take 14-16 months (complete guess) and get you dangerously close to that 18 month mark.
Just saying 2 year contracts aren't "stupid" as they were alluded to by the previous poster.
There will always be a newer phone, it makes me laugh when people say they are going to wait to try other phones. If you are in the market for a new phone, just buy one.
Samsung Galaxy Nexus
ROM: Team Sourcery!