For newborn/infant I usually just use the johnsons baby shampoo.

When DD turned about 1 I think i started using something more "fun", she picked a fun looking kids shampoo/conditioner in the supermarket & it was her "big girl" shampoo. We still use them but sometimes I put some conditioner in after I've washed her hair.

I think you just use what you like, I havent asked anyone else what they use but I do know my twin sister uses the same shampoo/conditioner (Dora) for her 5 yr old daughter as i do for my 3 yr old Daughter.

interesting subject though....