i would highly recommend the avh-p8400bh. It's a brand new deck by pioneer. It offers nav app for iphone so you can just stream your nav from your phone to your screen. You can also purchase the avic-u220 if you want nav built in.

By far one of the better units ive seen in the last 2 years. price around 699.99

We sell for less. :)

Also the U220 is extremely scarce because well...they are complete and utter garbage. In fact, most add-on navi units are junk in my honest opinion. Better to use MotionX as an app on your Iphone and run GPS navi from your phone to show up on the deck. Pretty sweeet!