I was having a little poke around the Pixologic site at the new ZBrush and ended up at Alan Camara's Blog where he has images of all manner of his character modelling projects. He lists several apps as his tools of the trade, that said it is his ZBrush modelling (high and low poly) that are pretty inspiring.
Check out his work for the Comicon Challenge where he modelled up Pitt.
[Pitt image from Alan Camara from his blog site]
The image below shows how the sculpt in ZBrush evolved - it is an interesting process starting with those funny looking ZSpheres. Definitely check out the full set of posts and comments on the Comicon Challenge site - there is lots to learn and it is great to see the progress.
[Pitt WIP images from Alan Camara from the Comicon Challenge boards]