You can never have enough hair for Poser or DazStudio. Fortunately for those of us on a tight budget there is a lot of really high quality hair out there for the various figures. The following is a quick rundown of some of what is available.
Kozaburo has a good selection of very high quality hair available in the downloads section of his site Digital Babes. the following is a sample of what is available:
Adorana has a good selection of dynamic hair and skull caps for V3 and M3 available on their site.
Ladyfyre Graphics has some free hair available. Two of these items were previously on sale at Renderosity but are now available free.