Iran is easy. The only complication for Americans or British is you need a minder. It's an added expense but pretty straight forward. I totally recommend it. Most people are so friendly it actually starts to become a problem to walk down the street without having to stop every 500 metres to talk to someone who wants to welcome you and ask if you have been to their home town yet, etc, etc. Bring books though. Not much to do at night in Iran ;)

That's why I said "almost" any. Though many of my friends have actually been to Iran and had great things to say.