There's never been a better time to install energy-efficient windows. Due to changes in tax law with the passage of the new stimulus bill, energy-efficient windows purchased in 2009 and 2010 are eligible for a tax credit equal to 30 percent of the cost, capped at $1,500. This is five times more tax credit than before. The law has some specific restrictions, which you can read at this page from Simonton Windows.
As a contractor I have seen such a spike in clients wanting windows for their home because of the government money for replacement windows
This tax incentive makes now a great time for homeowners to purchase new windows.