The lines were clean and the shading was nice
The shading was subtle yet stood out just enough for it to be appealing to the eye, especially in the undershirt/necktie area. The shading also complimented the thick brush strokes really well.
As for the wood, using a higher smoothing for the texture worked really well. However, I personally would have picked different shades of brown: a light tan for the main color and a slightly darker tan for the swirl pattern. (It would look something like this: http://bit.ly/fB59uU)
Something you may want to consider is reshaping your brush strokes after you've drawn them to make the thickness of the stroke more consistent.