A lot of it depends on what your son likes. Our nearly-two-year-old grandson is into taking things apart. He unloads the dishwasher and he takes everything out of the pantry. He is fascinated by nuts and bolts, knobs and screws. So from us for Christmas he is getting... a drill. A Fisher-Price one - it makes the appropriate noises but apparently he can't destroy the house with it. (He will try!)
He's also getting some books and a Veggie Tales DVD, plus a toy that lets him hammer balls through the appropriate holes - calculated to drive his parents crazy.
He already has a little bike which he loves, and he enjoys cars, trucks, and trains. But he likes things that work, not that are just to look at.
His birthday is the end of January, and he'll be getting some toy golf clubs and some art supplies (big fat washable crayons - not markers - and a big roll of kraft paper which his mama can put up on the wall).
Your son may be quite different. What does he like to play with when he has a choice?