After seeing the chart (on the right side of this page),
Solar Photovoltaic, PV Module, Panel Prices
I'm somewhat discouraged. It looks like prices are stuck in the 'expensive' zone and aren't likely to move until someone finds a cheaper way to make them and starts selling at $2 a watt.. (Unlikely to happen in my lifetime).
So, if you (like me) have been thinking of installing PV on the roof, you are probably not on thin ice if you remove the, "what if the prices drop" factor..