You will need to decide between "dynamic hair" (mentioned by amon_g, and "volumetric hair" (as mentioned by ernyoka). Dynamic hair is P5 only, but typically looks more realistic, and the P5 Hair room gives you a lot of control over how it looks (length, thickness, amount of waviness, etc.). One thing it doesn't do well are spiraled curls. But many people use "curls" to refer to waviness; length and waviness are easily configured with Dynamic hair. As mentioned, there are props in the marketplace both here and at RuntimeDNA that you could use for that. Volumetric hair (polygonal hair prop) can give very realistic hair sometimes (depending upon the quality of the prop). The amount of control is greatly dependent upon how the hair was created, and how many pre-defined morphs come with it. You can change hair with Poser magnets, but that's a tedious job. You can also created your own morphs in at external application; that's tedious as well (unless you do this for a living). However, AprilYSH's Spiral Curls are an excellent example of how volumetric hair can exceed the capabilities of Poser5 dynamic hair. (hmmm, too much info...?)