I usually use Cloudstar's Buddy Wash and Buddy Rinse. I think I got it from Jeffers, but can't remember. Unfortunately, nobody around here carries it. Lately, tho, I've been using Hypo Plus (from Groomer's Edge), followed by Buddy Rinse. The manager at Cherrybrook recommended it to me last year when Caleb was really itchy.
I currently use the furminator shampoo. It's like $10 a bottle. I bathe him every 2-4 weeks and have gone through most of my bottles of shampoo and conditioner in 6 months. I love how he smells after - it keeps the nasty dog odor contained for about 3 weeks and gets rid of tons of undercoat.