I have a droid since the day it came out, and I feel that for my needs it would be a perfect solution for a CarPC, maybe not the most integrated like some front ends that are on these forums, but functionality wise, it would do everything I need and more. the video out is the biggest set back in accomplishing this however. There is no easy way to make it a fully integrated solution.
I saw somewhere else on mp3car, the person that pseudo-integrated his Archos 5 (android based PMP), which is going in the right direction in my opinion, but with no google navigation (either because its not running 2.0, or because its not a 3g device), its a deal breaker. But i'm going to be patiently waiting for a 3g tablet like the Archos, because I think that 2.0+ with 3g, and google nav would make a CarPC thats much less of a hassle, and very functional.
It seems like many people are warming up to the idea of smartphones/PMP's replacing CarPC's.