I don't know about the Aveda, but with John Freida's you ahve to be careful...because if your hair is really fine and thin it can make it greasy looking. I've never really used it on completely straight hair.
Today I went to a salon and noticed that Matrix has a line for curly hair called curl.life defining system. I have think coarse curly hair, so I was wondering if anyone has used this line and what do you think of it?