In the pacific northwest (Seattle Area) my calculations show break even at around 18 years, which is pretty bad given that, the panels are only usually rated for 15 years.
Every few years I get to thinking about doing it and I run through the calculations and come up with similar numbers, panel prices are down, but power conditioning set-ups are still a big part of the cost, and then you have to pay for a contractor to install the setup (one of the largest parts of the cost) if you want to get any of the tax credits or connect to the grid.
Looking at my last utility bill, 99% of my energy is coming from non fossil fuel sources, hydroelectric mostly. So green guilt is not going to get me to put PV on my house and it doesn't really make economic sense either.
I'm sure I'll run the numbers again in a few years when I need to re-roof the house; I like the idea of energy independence, but where I live Solar PV is just not cost effective.