A sulfate free shampoo is nice to have if you experience buildup or accidentally use a non water soluble silicone and need to remove it. In order to remove silicones, you'll need a sulfate free shampoo that contains Cocamidopropyl Betaine or Cocobetaine. Straight cowashing works for some, so a sulfate free shampoo isn't necessarily a requirement.
If you're CG, the Garnier Fructis Triple Nutrition Ebonyrose mentioned has amodimethicone, a silicone which is not water soluble. Great conditioner, but no longer CG friendly. I believe Aussie Moist also contains a non water soluble silicone.
I have a good amount of fine hair, so several of my products have protein in them, which you'll want to avoid with your coarse and low porosity hair. In looking for products, you can spot a protein in an ingredients list if you see any of the following: gelatin, collagen, keratin, soy milk, anything "protein", anything "amino acids" or "hydrolyzed" anything. All those either are protein, contain protein, or are pieces of protein. So, they'll act like a protein when applied to your hair.
Some moisture only options I've used and liked are:
cowashes: Garnier Fructis Pure Clean, Suave Naturals Daily Clarifying, VO5 Vanilla Mint Tea
rinse outs: Renpure Argan Oil (mine is CG, but new bottles have added amodimethicone), Garnier Fructis Body Boost
My rinse outs double as leave ins, I just watch the amount I use so my hair doesn't look weighed down. Depending on the dewpoints and what my hair needs on a given day, my cowashes can sometimes double as rinse outs, however, my rinse out conditioners are all too heavy to make good cowashes.
CG since 11/2011
2c /3a F /Mii, low porosity
Clarifying: ACV rinses, Suave Professional Men Deep Clean Peppermint
Low Poo: Renpure Luxurious Argan Oil
Co-washes: VO5 Kiwi Lime Squeeze or Strawberries & Cream, Cure Care
RO: VO5 KLS or S&C or Shea Cashmere, Cure Care
LI (if needed): VO5 S&C or Renpure Luxurious Argan Oil (old formula)
PT: IAGirl's (every 2 weeks or as needed)