Kiplinger has released an interactive map of the country ranking the states by their tax-friendliness to retirees.
The 10 worst states for retirees are:
10) New York
9) New Jersey
8) Nebraska
7) California
6) Montana
5) Oregon
4) Minnesota
3) Rhode Island
2) Connecticut
1) Vermont
See the interactive map here.
Kiplinger explains the rankings here.