If you use NURBS to create your first models the chances are you'll end up getting so stressed out because they keep doing unexpected things or just don't do anything, that you'll give up the who 3D thing and end up having nightmares about surfaces that disapear and seams apearing everywear. It's safer to start with polys as you can usally predict who they will react and if you want that super smoth orangic look just convert to Sud-D. Also what happens if you've spent months learning to use NURBS and have an urge to make a game model.