The shampoos that get a lot of play on the forums include:
~ Nano Shampoo
~ Nizoral
~ Back to Basics Green Tea
~ Revivogen
~ Tricomin
AFAIK, the above list reflects those shampoos that many use because they are advertized to help w/ hairloss. Be informed though - that except in rare circumstances - a shampoo alone won't halt your hairloss or regrow your hair.
PS: They're all a bit pricey. But considering 1 bottle might last you 7 months to 1 year - it's not really that bad except for the initial outlay.