My parents really surprised me this year by giving me a deionizer - not sure what I did OR didn't do to deserve it.
I was able to try it out yesterday and I was shocked how good it works. You simply wash your vehicle (like normal) and you use the deionized water to do the final rinse. You then just walk away and let your vehicle dry on its' own.
It went against every bone in my body not to dry my truck, but it turned out amazing.
It's quite expensive, but definitely worth the investment, if you wash your vehicles frequently.