In New Scientist last week they discussed this very issue. The conclusion seemed to me at least to suggest that there is still a great deal of change going on the in the human genome.
They cited the example of the appearance of the gene that allows adults to digest milk, which is apparently a pretty recent (as in the last 5000 years?) innovation. There are also other genes that have spread like wildfire and might have only been around for between 3000 and 500 years.