I'd drop the motherboard down to one in the $100-140 range (like this one: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157296),
drop the caviar black down to a Caviar blue, and spend the saved ~$120-160 on upgrading the GPU to the 7950 or GTX 670. You'll have much better performance than that setup. Other than that, looks good.
23" should be great. Just look for 1080p and somewhat low response time (<=5ms)