Here you go, I posted this on another thread.
I've got this touchscreen head unit in my 300, but they're about £500 so depends on how much you're looking to spend. It's a kenwood DNX5220BT.
It basically does everything you could ever want.
Radio, SAT NAV, phone, DVD + CD player, TV, I pod/iPhone connection either Bluetooth or charger cable which charges. USB connection. It remembers your phone so connects via Bluetooth instantly.
Everything on your phone is accessible via the head unit. Contacts, SMS, music, videos.
It's not voice activated but your contact list comes up on the screen and you can save 6 quick dial numbers so it's just one button press to call on the head unit.
It's fantastic to be honest. :)