I have had good luck with Expert Gardener. Available at Wal-Mart. Fox Farm is a great company for a more higher end soil.
Fox Farm Ocean Forest is great soil however can't find it everywhere only mostly at hydro stores. Miracle Grow Organic Soil isn't bad however does have fungus gnats in them sometimes. Just get a soil that says organic and on the back doesn't have any continous release feeding, or no NPK values. The MG Organic has some NPK but it is very miniscule.