It's shaping up nicely. Your topology flows well but is unnecessarily heavy in areas, for instance the deltoid isn't defining much. These polys could instead be used to better define the ear or finger.
I'm not sure what program you're using but it looks like your smoothing normals are all jacked up. In Maya these are defined by hard/soft edges. In Max these are defined by smoothing groups.
Oh yeah if i were doing something that had really defined muscle i would definately do that, but thats extreme overkill for a model like this. Less really is better here imo.
I'd definately try and define the wrist a little bit more. Right now his forearm just kinda noodles into a hand. Makes one wonder how that proves to be very functional, yes?
oh shit Tim - thats really hot- a definate progression from the first sketches you did! Got that MR Rockstar last competition entry feel going on but that's definately not a bad thing.