Are you a new investor? No client of mine has ever asked that question when searching for a property, they pretty much all know Texas has the HIGHEST.

Definitely check out CO property taxes. I have no direct links to send you too, maybe CJ's is a good one.
But, I'll tell you I work with a lot of relocators and they are always shocked at how low our property taxes are in Colorado Springs.
Be careful not to only look at State taxes but also county and city. Although, the state property tax might be low the local property tax might be high.
Lastly, I've been told in the past if there is no state income tax the property taxes are higher and vice versa.
I relocated from Dallas TX, where property taxes are very high. And, still find even with the state income tax my taxes in general are lower.
The same equivalent house in Dallas runs about $3000 more a year on average in regards to property taxes.
Good luck!
Susan Walker

Besides looking through the Trulia information you might also want to visit this site
Tax sites and other tax info all states (private site)
http://www.taxsites.com/state.html

This is posted under Austin. I think you might want to post it under another category.