I'll tack here and ask "How High?" A tall ceiling gives you room to store stuff or even create a loft. Incredible amount of storage space + it gets stuff off the floor, freeing up room where you walk, by storing it up high where it's out-of-the-way (and you don't walk....). Plus it allows you to have a taller garage door.
Heck, then you could install a car LIFT! Easy under-chassis access, no fuss oil changes, no more ramps, lift the car to a comfortable height for wheel-level work, vacuuming out the interior, etc.
Even more possibilities!
Think about it.....