Selling is a personal decision and we all have our own reasons for selling when we do.
Big John layed out some real concerns about selling and buying back and the potential to get caught in a trap.
You do hit on a point that while not likely to occur has popped into my mind. This Administration will allow the Bush tax cuts to expire so the Fed rate will naturally go from 15% to 20%.
We know these Bozo's in DC have declared war on anyone who makes more than $250,000 per year so the 20% rate could be at risk. Dare they try to increase it? Certainly they dare! If we see evidence of that later in the year there will be lots of selling for tax reasons. Not to mention those states who now give cap gain treatment are re-thinking that, as a means to increase their revenues.
Your thought patterns are good, but in my opinion, too soon to do any selling. But keep monitoring it.