Turning a box model into a nurbs

I was wondering if there is any way to change a complex box model into a smoother polygonal piece so it will have less deformation when texturing…it sounds like the easy way out but i noticed in subsurf the lines flow much better. When i see tutorials on the web featuring nurbs, it seems like there is barely any mistakes made in the faces…and a simple line form would make texturing much more of a breeze.

AFIK you cannot go from mesh to NURBS. What is wrond with using subsurf, though?