I have found that my gray hair looked yellowish when I used a regular shampoo (any brand). I bought some generic shampoo at Sally Beauty which is made to eliminate the yellow tones. It even has a conditioner that works really well on gray hair. It wasn't expensive either.

I don't like the upkeep on dye jobs. And some are very drying. One woman here at work has hair that feels like straw from over working it. I keep wondering when it will all fall out!