i'm a huge fan of subsurf modelling, also known as subdivision modelling. this is making a model based on quads and then using the subsurf
tool to make an incredibly smooth, detailed model. this site
is a great place to see what's possible with subsurf modeling.
models made for subsurf modelling aren't suitable for use as game models because they use a lot of small faces to control the flow of the subsurf that wouldn't make sense to use in a game model. what suburf models are good for is generating normal maps
for game models. once the high detail subsurfed model is made then a lower detail, triangle based game model is made and a normal map is generated using the high detail model as the template.
the subsurf model can also be lit and radiosity baked to generate a lightmap that can be used as the basis of the skin for the model. this page
has some good images that demonstrate the process. (although the instructions are out of date because blender's tools have changed).