I totally agree! This is much more important than absolute rarity. A coin from Vanuatu or Togo with a mintage of 500 is never going to be as valuable as a coin with the same mintage from Russia or China. Coins from those two countries are hot because of their unprecedented economic growth. For example, I was fortunate to acquire a couple of Russian mint sets from the mid 90's for about $10 apiece which now sell in the hundreds of dollars. It turns out that due to the hyperinflation during the Yeltsin years the standard circulating denominations were produced only for mint sets in 1995 and 1996. As a result, these coins are in demand by everyone putting together a type set, and since living standards and disposable income have risen so much during the past decade there are many more ordinary Russians driving demand. However, there is a flip side to that as I am interested to see how the current problems in the Russian economy will impact prices of Russian coins. I wonder what prices of coins from "up and coming" Asian economies such as Vietnam, Malaysia, Indonesia, etc. are doing?
Good points. I'm currently collecting classic silver commems by type for partly that reason (the others being historical significance, a varied set of designs, and reasonable challenge) On your other points, it seems like South Korea, Brazil, Mexico and the Philippines would look pretty good, and possibly, as a longer shot, Columbia. Now, I just have to find which one has the coolest coins. I'm already kind of a fan of Philippine and Mexican coinage, so maybe I'll look there first.