i was just wondering how you all decide what type of modelling to go with?

as there are a few different ways of modelling everything, its hard, especially for a newbie to know what approach to take when modelling.

is there a general rule of thumb - say for example nurbs for organics / poly's for hard surfaces / sub division for hands.

then there is the different ways of using them all like drawing the curves the lofting the surface or start with a box to box out the rough shape before adding detail or a plane then extrude the edges out etc.

any help much appreciated