thanks for the words of encouragement.
Yeah retopo, dismaps and Normal Mapping. Its a mine field mate. Everyone has different opinions on all 3.
Topology: Always a fun topic, I love it as I've always thought myself of being a hardcore modeller, even more so now I am in the industry. I think most people with tell you these days, you gotta have quads (moreso in film) and your edgeloops have gotta be 'there', without edgeloops people may aswell forget good deformation, particularly in a Face/head model. If you look at a good mesh, and the artist knows his or her stuff then the loops will near enough match the direction of the muscles that lay beneath the surface of the skin. Its great to sculpt from a blank sphere or cube in ZBrush but you dont get good loops from the offset, and in my opinion doing something again to create the proper geometry is a waste of time and effort when you could have done it the first time round with an importedmesh from Maya,soft etc....
Dismaps: Yeah great as long as you can get them to work in Mental Ray properly, if you want them to work in a superior way without arsing about, then renderman is the answer. Failing that theres always Cyslice. Just import the low rez mesh and the hi rez one from Zbrush and it will work out the difference between the two and produce a stunning map for little or next to no effort.
Having recently read that the characters in Avatar had no displacements whatsoever because of dissolve issues between the different expressions I can actually understand that - why put yourself and the team thru so much pain in order to get it right when the info can be built on the mesh already without resorting to image maps at rendertime....afterall a few years back what the hell did we do?? We did it the very same way and applied a damn good bump map!
Normal maps: AKA the Super Bump Map! great if you are into realtime stuff or just wanna add extra kick to your models without the aid of Dismaps pushing the Geo out left right and centre and without the long render times. According to a Siggraph paper this year Normal Maps can be used in a specific way to now drive Subsurface Scattering in a skin shader, again all based off the normals....
Overall though I would use try and use these methods and see what feels best, always try and think about the end result, whats it for etc...what will benefit me
remember too that alot of work (as good as they are) on the forums are really highly detailed just to show it off, none really have a workable factor built in for animation etc and most end up in portfolios 'posed to sell'.
At the end of the day the knowledge gained in these areas will help you move forward and make the vital decisions when needed as Ive mentioned above
hope that helps...happy new year