The best "investment" you can make for a drying aid is a mixed bed water de-ionizer. Deionized water makes all the difference and you can basically just let the car dry itself. The next best thing is a Master Blaster - for touch free drying to get all the water out of the cracks, etc...
This may not be the fastest or the cheapest way to dry the car - but it's the best way. Most QDs work fine as drying aids, which is a term I have no problem with. They aid you in doing a quality job of drying the car - so the term seems reasonable to me.
Some of the ones I like are FK 425, Wizzards M & S, Prima Hydro, Duragloss AW,PBs Spray & Gloss, UWW+, Pinnacle Rinseless, Prima Slick, Vic's QD, Sonax BSD, and pretty much any quality QD or spray wax that is "slick" and doesn't streak.