Countries Llike Cuba, Nazi Germany, Mao China, North Korea, Mussilini Italy

You could add USA now when Obama substitutes a phone and a pen for the rule of law.

Honestly, I've just been to Iran again a few weeks ago and I can't completely agree with you that it should be on this list. The power there is divided between the ayatollahs and the politicians and right now they really don't go along very well. Rohani is too progressive and open for the religious leaders, but he's still chosen by the people via a democratic election so they have to get along somehow. The people in that country are generally more on Rohani's side but don't really want to start a revolt against Khamenei and his bunch of imams. Most people seem to agree on a balance between religious and worldly power, that's why the shah is still forced to living abroad, dreaming about regaining power one day. Iran got a horrible reputation worldwide due to Khomeini openly disliking and being needlessly provocative towards the West and especially the USA, being topped by Ahmedinejad later on with his stubborn and uncooperative international politics concerning a.o. nuclear power. The people generally disliked Ahmedinejads politics and really hated to see the banking embargo in place (which caused something close to hyperinflation by now) so that's why they voted him out of office. Voted, as in via democratic means. The general tendency also seems to be that religion isn't something democratic. I guess most Americans don't vote for their local priest either in an election, while they do chose a mayor and president.
Due to this, I think Iran shouldn't be on this list, but probably (due to Khomeini and Khamenei and their gang) get an honorable mention or so. :)
In addition, if you ever get a chance to visit, do so. It's not as bad as the media tells you. People are extremely friendly, there's lots to see and do and real golden Pahlavi coins can be found at many places for very attractive prices, as locals also widely use them as investment (and due to the current inflation levels there's also a huge amount of different circulation coins to be found).

I'm too young to have visited wartime Japan, but for what I heard and read it should be on the list. :)

I'd echo that ancient Rome had some good ones.

Caligula went off the deep end and appointed his favorite horse to a position in the Senate, then declared war on Neptune and had his soldiers stab the water.

Nero allegedly burned half of Rome to clear out room for his palace complex.

Commodus legitimately thought he was Hercules, and also renamed Rome and everything in it after himself.

Elagabalus hosted a posh dinner party, but instead of serving dessert, he unleashed a pack of starving leopards into the dining room.

Honorius went into a panic when a messenger told him that Roma had perished. He was greatly relieved to find that his favorite chicken, Roma, was alive and well, and his capital city had merely been sacked by Vandals.

I mean all past and present dictator regimes, even from a thousand years ago or longer, up to today. I am trying to put together a list of all of these countries, then create a collection of the coins of those regimes. I already have some of the obvious ones such as the USSR, fascist Italy, Nazi Germany, Cuba, etc. in almost uncirculated condition, but obviously some of the countries you all have mentioned are going to be hard to find in that condition.

Tricky.

"Dictatorship" is often in the eye of the beholder. I'm sure there were monarchists in colonial America who thought George Washington was a dictator.

Further, many "dictators", particularly in the modern era, would have claimed to be democratic. The Communists of Russia and Eastern Europe during the cold war and the Ba'ath Party rulers of Iraq and Syria would all have claimed to be democratic; after all, they all held elections; that they were one-party elections is beside the point. Mugabe's Zimbabwe is theoretically a multiparty democracy, but supporters of opposition parties are intimidated by violence against voting or running for office.

We could perhaps offer a technical definition: a "dictator" is someone who wields supreme power and authority over a nation, but who is not a monarch and is not democratically elected in a multiparty system.

Dictatorship usually involves some kind of personality cult around the dictator, but not always. Burma was, until recently, considered a dictatorship, but the military rulers of the junta were largely faceless men, unknown and unrecognized either within the country or outside of it.

The office of "Dictator" was one invented by the Romans. The government structure of the old Roman Republic was deliberately designed to be complex and convoluted, making it impossible for any one person to take over the government and become a king. but Rome's founders realised that in times of national emergency, someone would need to cut through the red tape to get things done quickly. So they allowed for the appointment of a (temporary) Dictator, to rule for the duration of the emergency. Of course, folks like Julius Caesar came along and realised all they had to do to stay in power indefinitely was to make sure the "emergency" never ended.

In ancient Greek culture, the equivalent office was "tyrant", a word which originally did not carry the connotations of arbitrary cruelty and injustice that the word carries today.

I think Sap nailed it. A big problem with "collecting coins of dictators" is that often they are not as impressive or interesting as the coins of Nazi Germany, fascist Italy, or the early war Japanese coins. The Philippines were under the grip of Ferdinand Marcos for a pretty good chunk of the 70s, but 1970s Philippine coins aren't especially interesting to collect.

I would recommend that you choose a sub-set of dictators to start with before jumping into "all dictators since forever".

You could do dictators who came to power as Democratically elected officials, but then exploited a loophole or tricked the populace into voting their democracy away.

Or you could do the appointed dictators of a state ruled by a single party, like any of the Communist bloc.

Or a fun idea would be to collect the coinage of warlords and military dictators. China had some colorful figures between the collapse of the Qing dynasty and the Communist takeover.

The crown prince took the oath in Egypt after his father died, making him the Shah, according to himself and his followers. There's just one tiny issue: he should do it in front of the Iranian parliament to be valid. So there is a Shah and he actually hasn't given up his claim to the throne.