Here’s a quick study done completely in zbrush, with an imported cube from xsi. Can’t say this is the best way to model a skull but it’s by far the most fun 
I see a lot of potential for zbrush as a sort of fine art tool, because of how fast you can move things around. Next time though, it would be more useful to have a base skull model imported with the right topology, etc.
very neato 
Great modeling and welcome to Zbcentral!
nice skull!
can you say why you imported a cube, instead of use a cube primitive from Zbrush, or a Zsphere?
thanks,
Cube primitives in Zbrush look like they have poles where many edges terminate at one of two vertices (call them the north and south pole if that helps), which would make them not much different from using the spheres Zbrush makes (not to be confused with Zspheres). Create one in ZB and turn on polyframe to see for yourself.
I was experimenting the other day using a 6 poly sphere with 2 iterations of mesh smooth on it made in 3DS Max exported to Zbrush. I’m also not sure this is the best way to go about modeling. In some circumstance I got severe jaggies when modeling details in certain areas that needed constant smoothing, but otehrwise it seemed to work alright for the most part as long as the subdivision was high enough. Seemed better than a regular sphere or cube in ZB anyways.
Cool Hamlet Skull study 
Pilou
[ambient-whisper]- thanks (especially for all the tips when starting up with zb) 
[jsunandmax} - i just wanted to start with a primitive that had a symmetry line and would smooth correctly when subdivided. I’ve also found that spheres in ZB don’t have a centerline in the YZ plane, so the logical thing was to make a quick one in another package and go from there.
From this little experiment i realized that you really want to work with objects that have some level of localized detail before you start subdividing. This way, most of the density in the model will be in areas of high detail (like the eyes, mouth and nose) and less on places like the back of the head.
The one thing that still bugs me and REALLY needs a fix is the ability to work on a perspective camera with a variable focal length. As it is right now it is very hard to work in zbrush from observation because what you’re looking at in real life (in this case a real skull cast) won’t translate well in zb because it is “flattened” by the camera. I’ve heard that the reason why zb uses an ortho camera is because it renders much faster and performance is better especially with high polygon counts. So, if only you were able to switch to, say a 50mm focal length at the lowest levels of subdivision (maybe under 100k polys), things would be a lot easier and would mimic real life sculpting much more
thanks for the answer. could you post image of the base cube you imported? Just to show how much subdivision was there?
thanks!
beautiful, elegant modelling. I think thats a great idea importing a cube as the poles in zbrush prims leave you with that tight area (usually top of head &bottom of neck/shoulders) that just wont smooth right. I assume that is your reason?
Anyway, lovely work.
Add a flame effect and you got ghost rider. 
I just used that technique of importing a cube from another prog (in my case Modo), for a product design and it worked beautifully! It may be only a relatively small tip, but everyone should try it, it is inspired! I dont think I’ll use Zbrush prims again (but then I usually start with zspheres anyway, and will continue to do so).
Thanks again!
You can use the zsphere primitive to do this and a fella posted back at least a year ago the perfect sphere that solves all this, not sure what he called it. Perhaps someone else will remember. I think it started with an ‘l’, but it was pretty impressive.
That said, nice skull. Could just be the shot, but looks a little tall on top, then again it might have an unusually large brain stuffed in that shell.
nice job. And only in 3 simple steps
nice work, lots of mass, did you use refference or is this your interpritation of a scull? well done.