I'll add my 2 (euro)cents into the head&shoulders debate.
I had lots of dandruff when I was a kid. H&S got rid of it, but it's true that I started experiencing gradual more quantity in hair loss the longer I used it. Lucky for me, the dandruff was hormone related, so once I grew up and got out of puberty, it wasn't any longer necessary to use it.
Then I got another skin problem in exchange, but that would lead me too far... LOL.
Anyway, things like Fructis or Dove weren't much better, since they contain silicons that give you the illusion of nice hair, while the silicons weigh it down and don't really help recover the breakage.
I'd go with the Nioxin suggestion Lynne gave you as well.
I think Redken has a product too, but I'm not sure. I'll ask my hairdresser next week as well.