If you a CA resident, you should go to Western to save as much money as possible. The tuition is also cheaper. The only thing that scares me about Western is that their building is delayed and wont be finished until December of 2009 at the earliest. Also as a new class/school they will try new things etc. that could be good/bad etc. NYU on the otherhand is already established and you pretty much can anticipate what happens your 4 years just by talking to upper-classmen.
Western is also in more of a suburban area so depending on your lifestyle you should factor that into your consideration as well. Regardless you'll eventually get your DMD or DDS
NYU hands down my friend.. im from CA too and even though Western is a cool school, it's not even accredited yet so you are honestly taking a big risk and the school offers no specialty positions yet if u decide to advance in ur degree. Getting out of Cali for a bit isnt so bad.. =)