I'm in the same boat as rankourabu, I've been to more than 100 countries and it's getting harder and harder to decide where to go. My goal was never the visit all the countries in the world, but I'm told by friends I should go for it as I've travelled a lot. I like to see new sights and don't care to keep seeing sights similar to what I've seen elsewhere. To make matters worse, I refuse to go to places that have little or no tourist infrastructure, camping and roughing it are define no nos. Trips on a whim are usually to places where I've already been and a lot of the destinations where I have not been to require advance planning/visas, etc. I'm not the kind of person who justs wants to check a country off my list, I'd rather SEE a country I visit and won't just rush through it just for the sake of getting to another country.

To answer the op, here are my thoughts:-

Bhutan is a little difficult to get to as it requires planning in advance (processing of visas, etc) and flight schedules to/from Paro are not extensive. I've been to Bhutan and it was well worth the effort.

Syria is going to be extremely difficult now because of the current situation. Was there in 2010 and it was wonderful country to visit, would never think of visiting the country now.

Never been to North Korea, and it will be interesting to see what changes happen there after Kim Jong-il's death, and if the country opens up to tourism.

Saudi Arabia will be a difficult country to visit.

rankourabu, make sure you go on a sea plane in the Maldives, the views are amazing.