Stamps of Israel and the Palestine Mandate are popular among stamp collectors in Israel and among Jewish collectors throughout the world. Stamps of the British Mandate Period are of particular interest from an investment standpoint, because they also appeal to British Commonwealth collectors. In all likelihood, the vast majority of Palestine #1s were used and discarded, and there remain no more than three to six thousand, in any condition.
Many of the newly independent and newly resurrected nations of Europe and Central Asia have issued popular topical sets and souvenir sheets in modest quantities, and most are currently very inexpensive. I view such issues as low-risk speculations, as only time will tell whether either the development of stamp markets within these countries or topical appeal will push them significantly higher. In a sense, they're comparable to penny stocks, but not as risky.
The Gordon set strongly appeals to British Commonwealth collectors, as it beautifully illustrates the histrionic hubris and heroics of the former Empire. Only 5,500 were issued, and Scott '10 values it unused at $275.00 . I recommend the set based on my confidence in the growth of the British Commonwealth market, although it's possible that demand for it will receive an additional push should Sudan ever become a normal country.
Currently, Sudan is a nation of about 42 million people, living under what is perhaps the most vicious regime on the planet. It has suffered several civil wars over the last 50 years, including the current one being waged in Darfur, which has earned the government international condemnation and charges of genocide. The country is oil-rich, and currently exports over 180 million barrels per year. It also has significant deposits of natural gas, gold, silver, chrome, asbestos, manganese, gypsum, mica, zinc, iron, lead, uranium, copper, kaolin, cobalt, granite, nickel, tin, and aluminum. Agriculture production remains Sudan's most important sector, employing 80% of the workforce and contributing 39% of GDP, but most farms remain rain-fed and susceptible to drought. Political instability,adverse weather, and weak world agricultural prices ensures that much of the population will remain at or below the poverty line for years. Annual GDP growth has been very high, averaging almost 8% over the last five years. However, it is very likely that most (or all) of the prosperity has benefited only the ruling elite, as Sudan is not only one of the world's most murderous countries, but also one of the most corrupt.
That an attractive, historically significant set of stamps with such a meager printing quantity and some worldwide appeal, from a medium-sized country with valuable natural resources, is currently valued so low indicates a nearly total lack of a stamp market within that country, which is not surprising if the country is being run by mass murderers who do not care about the welfare of their fellow citizens. At worst, the Gordon set represents a conservative investment. If Sudan's situation improves, there will be ample reward for the patient investor who is willing to get in on the ground floor.
South Korea, a nation of about 50 million people, is one of the fastest growing economies in the world. Currently, it is the world's 13th largest economy and eighth largest exporter. It's export-fueled economic growth has led to a miraculous explosion in its GDP, from almost nothing 50 years ago to about $1 trillion today. Annual GDP growth has averaged 4.2% over the last 5 years, reflecting a slowdown in 2009 due to the global financial crisis. Furthermore, South Korea may be the most rapidly aging nation on earth, as its 65+ population is expected to more than quadruple from 9% in 2005 to 38% in 2050. Obviously, this could pose economic challenges for the country, but it will almost certainly add to its stamp collecting population.