I'm all for the poll idea, but can we assume that members will vote for the sites objectively? Do we care if the votes are biased? We all like a great looking design but fewer people give a damn if the code behind it is woeful! And accessibility, would the general member really care?
Should they care?
On a plus side, it would be a doddle to set up - just set the polls to expire after 7 days and assign one person to "announce" a winner.