I'm planning my first trip to Vaduz in eighteen years and stumbled across this site - just wanted to post a personal note about Prince Hans Adam, since what I've read here is somewhat distant from him as a person.
A gentleman at the tiny cafe I frequented there spoke to me often about politics, and he introduced the prince to me one day. We chatted for awhile, and he was amazingly friendly. I saw him several more times while in Vaduz, and he always made it a point to say hello. Coming from the US, I was unused to the idea of royalty being accessible - even the politicians I knew were usually loftily apart from the general populace! - and was utterly charmed that a prince would talk with me.
I wrote him a note after I returned home, just as a thank-you for having contributed to the wonderful experience I had spending time in his lovely country. He sent a note back, along with a book about Liechtenstein. To this day his egalitarian attitude remains the most enduring memory of my trip.