I also use Hydroton, purchased from RepotMe but I'm not sure they have the best price on that product. I've been using it almost 2 years now, and my wide variety of plants are thriving in it.
Thank to Ray for the info on the ATAMI PrimeAgra. I checked Tom's site just now, but it's under construction. Will check back in a few weeks. Hopefully he still carries it, I'd like to compare it to the Hydroton.