Nexus 7 tablet, rooted, custom kernel (Timur)
Tablet has USB OTG Y-splitter cable which provides power and USB capabilities. One end supplies power from 12v CIG charger, other end is connected to USB Hub. USB hub has 1TB HDD, USB micro receiver for Logitech Wireless Controllers and USB DAC connected to AUX in for car audio.
NFC sticker in cup holder spawns WiFi hotspot, Bluetooth text & call sync to tablet from phone when phone is placed on it.
Tasker, GMD Gesture Pro,and Timur kernel were essentials for me. Worth it for Google Maps Navigation alone. And the fact that my passengers can play Roms on long car trips is a plus!