I have thick, curly hair as well and finding a great product that really WORKS has been like finding the holy grail.

I finally found my my HG shampoo and conditioner - yes, it's sulfate free, doesn't contain a lot of ingredients you can't pronounce and no silicones that create that false sense of softness that disappears within a couple weeks.
I use Sudzz FX - usually found in hi-end beauty supply stores and salons.
It's expensive but truly concentrated and a little goes a long way. I've actually saved $$ by buying the 33 [liter size] of conditioner since I tend to use 3x more conditioner than shampoo. Sudzz FX truly is miraculous stuff - the amount I use daily is about the size of a quarter and it evenly distributes throughout my hair - I've tried many other hi-end conditioners and either they didn't work or I had to use so much product I couldn't afford it.
Trust me, this stuff works and it smells good too!