It is impossible to predict what actions Congress might take with tax rates, but in my opinion it is unlikely they will lower the long term capital gain rates and there is at least some risk that tax rates on capital gains increase in 2013 and beyond, so I think it is unlikely you would loose out by locking in your gain in 2012 at the current long term rates.

But that is just an opinion.

I've been doing this for 36 years ... here's how to control the bet. Options were created as a form of insurance to protect your portfolio during highly uncertain times. Talk with your broker about putting on a option spread that will protect you if the value goes up or if the value goes down. You can go out 30, 60, 90 days or 120 days. The longer view you take, the more expensive.

It's easy, but you will have to pay for covering your assets.