In the past I said any country that has the death penalty, because being a tourist there = you support the local economy = indirectly, through VAT etc, you support the government who thinks they can just take somebody's life.
I have more or less reviewed that opinion to countries only that use the death penalty on frequent basis. Otherwise, if I take this too strictly, I'd need to remove places like Mongolia, Lebanon, Jordan, etc from the list and those places attract me a bit too much to want to skip them. So instead the blacklist contains only those countries that are war-torn or where the dislike with the government is just too strong. I would for example not mind visiting California or Lebanon, they have the death penalty but use it quite rarely.
Countries and areas I'd not like to visit:
Texas
Florida
Ohio
Somalia (at least while the war's ongoing, once peace has been restored I'd not mind visiting)
Afghanistan (idem dito)
Saudi Arabia (but would LOVE to visit as soon as the local laws become a bit more flexible)
Singapore
In theory North Korea should be on that list, but somehow the place fascinates me because it's so unlike any other country in the world. This is one where I'm divided between my principles of not supporting cruel regimes, but on the other hand being very fascinated and curious at the same time.