I used professional styling shampoo and condition: Tresemme Shampoo for Red Hair, and John Freida's for Red Hair Conditioner. It's expensive, especially the John Freida products, but it works very well. It smells nice and keeps my hair nice and red.

I need to get the John Freida Red Radiance shampoo as well, but the conditioner is about $10 per small-ish tube, so I fear to picture that the shampoo would cost.