If you plan on taking advantage of the federal tax credits for energy-efficient home improvements, or even if you don't, check with your state and local tax officials, too. They also might have some tax breaks in this area.
The clickable map at the Database for State Incentives for Renewables and Efficiencies (DSIRE) is a good place to start. I just learned that Texas allows homeowners a property tax exemption in connection with solar or wind powered energy systems added to a residence.
Wow, so if I can come up with a more personal size wind turbine (like those above my cousin and I saw outside of Fort Stockton when we were on our West Texas jaunt), I can cut our property tax bill even more? Cool!
And if you're looking for even more federal savings, tax and otherwise, the DSIRE site also has a mini-map icon that'll take you to a list of financial incentives, offered by several U.S. agencies, that promote renewable energy and energy efficiency.