ADVERTISING NATIONS
Indonesia
The largest Muslim nation in the world, a key economic player in the region and a future world power. A population of over 230 million, Indonesia is a burgeoning country. It has a military of 300,000 and a history, though declining, of human rights abuses. Politically, it is a founding member of ASEAN and the non-aligned movement. It's also a key area of terrorism, including bombings in Bali and Jakarta. It is an essential country for any debate, especially in Asia.
South Africa
South Africa is one of the leaders of the emerging continent of Africa. One of the richest and most populous nations, it is a key voice in any debate, a true voice of the developing world. It is also a member of the G8+5 and is a possible future member of the UN Security Council. It's an important member of the African Union and Commonwealth. They have sent peacekeepers to some of the hottest trouble spots in the world.
Zimbabwe/Côte d'Ivoire/Sudan/Burundi/Rwanda
Lets take a look at the more controversial African nations.
A dictator ruling a country in trouble, civil strife and mass-murder or Genocide. Any of these provide an incredible platform for debating and are certain to be able to improve the MUN. They aren't as hard as they look, and only require a bit of research to become a thorn in the side of every MUN rep. If you're active enough, a resolution is bound to revolve around your nation.
Georgia
This small Caucasian state recently had the eyes of the entire world upon it, when it went to war with Russia...or Russia went to war with it, we're still debating that. Russia is only going to get more expansionist in RL, so perhaps Georgia will need to help defend other nations against Russian aggression. Ukraine perhaps, another nation you can still represent.
Sri Lanka
Whilst most of the world was distracted with the Israeli-Gazan conflict of late 2008, Sri Lanka again erupted in civil war. This is practically guaranteed to be a major source of conflict over the next few months/years and there's never been a better time to apply to represent it.
Finland
Always a key voice of reason and neutrality, we've never needed a rep for Finland more than now. With the Middle East, Asia and Africa starting to hot up, a representative willing and able to draft resolutions and propose new and innovative solutions to the world's problems.
San Marino/Bhutan/Grenada/Seychelles
Relatively small nations like this are the perfect opportunity to build up your skills and confidence as a representative, before graduating to larger, more important countries. Or not - every country is valuable, it's the rep that's important.
International Panel on Climate Change
Ideal for the committed environmentalist, this MUN-only position will allow you to help create a greener world.
European Union
A possible future superpower, this is the worlds largest trading bloc and with two members of the SC as members, with one more applying or possibly a plan for an EU SC seat in the works, the European Union offers a way to apply substantial pressure or offer substantial rewards to the world's “rouge” nations. A representative for the European Union will be expected to propose new resolutions, with a supporter, and co-operate with other nations to try and stop global conflicts, possibly be supplying peacekeepers to the world's hotspots.
Only really for more experienced reps or those candidates who can prove they'd be able to handle the role.