Car stereo decisions

So I am picking up a 2006 Mustang (hopefully tonight, probably tomorrow) and the only thing that was less than to my satisfaction was the Stereo.

The last time I bought a stereo was a (for it's time) awesome Alpine head unit with an iPod attachment.

Since then, I don't have my old iPod anymore and am close to jumping ship from Apple (let's just say that a red Lumia 920 will match nicely with the car I'm getting), and in the newer models that I've rented, I got pretty happy with some of the creature comforts like Bluetooth audio and handsfree calling.

The car will accept Double Din pretty easily but the fitting kit comes with a single DIN attachment too. I'm not too concerned with (in fact, I'd rather not have) a CD player. I don't want to watch movies on it, the car is there to drive, not to be an extra living room. Navigation I can give or take, same with a rear view camera, but I don't really want to spend over $500 on it, as I'd like to do things like get a new exhaust system, CAI and remap the ECU (ooh, if there's a head unit that can tie into ODBII, that would be awesome, though!).

Hopefully The Verge has some gearheads on here!