I've always had issues with Dry Scalp and Dandruff, particularly during the winter. Over the past couple years, I've also developed some sort of scalp sores that when picked at tend to bleed. They seem to continually come back.
I've tried a number of shampoos - Head and Shoulders, Nizoral, Aveda Pureformance, T/Gel, American Crew, etc. with varying results.