I've enjoyed using Jack Black True Volume Thickening Shampoo.  It smells nice - sorta fruity and sorta minty at the same time.  It's a clear formula, so there's no worries about dyes if that's a concern for you.  It's thick and it lathers really well.  It doesn't leave my hair feeling like straw, neither does it leave my hair feeling greasy.  When dry, my hair does look and feel full.  I can't testify about it keeping the scalp from flaking since I don't have that problem.  I like the fact that the shampoo is made with natural ingredients so I don't have to scrutinize the label for cancer causing "ates" and "ites".  I just don't know that the shampoo is worth the price.  It's definitely worth a try, though.