R.K.
Oxyclean! It has removed food stains that I thought would never come out. I routinely put a big scoop in my light colored loads and we rarely ever have food stains. If we do, a concentrated dose of Oxyclean on the stain usually does the trick. I buy the stuff at Costco in a big box, that's how much I love it.
Dirt, though, is another matter. Oxyclean works wonders on organic material, but it's not so great for mud, grease, etc.