That depends on how you measure it.
Today.
– The current ranks and leaders:
http://www.eia.gov/todayinenergy/detail.cfm?id=6090
– Recent increases by state:
http://www.eia.gov/todayinenergy/detail.cfm?id=5750
The Future.
California, Minnesota, Maine, Colorado, and New York have the strongest regulations to require renewable power in the future as a portion of their total. Each has a target to achieve 30% or more at or before the end of the decade. (Hawaii receives an honorable mention with a target of 40% by 2030, but only 25% by 2020.) More at:
http://www.eia.gov/energy_in_brief/article/renewable_portfolio_standards.cfm
No matter how you measure it, the good news is that most states have RPS. For more on this, see:
http://www.eia.gov/todayinenergy/detail.cfm?id=4850