How about just using a Combo Box?

^{download bmml source – Wireframes created with Balsamiq Mockups}

By a user being required to just choose what country they are from, it removes the unnecessary step of a user needing to first select the region (or you can just infer the region based on the country selected if needed). Allowing a user to start typing the country they are from will also narrow down the options available to choose from (an advantage over listing all options available in a dropdown list / graphically).

Smashing Magazine wrote an article about redesigning the way countries can be selected (they landed on using a combo box too). They documented their design process for this quite nicely too and is worth reading.

How about just using a Combo Box?

^{download bmml source – Wireframes created with Balsamiq Mockups}

By a user being required to just choose what country they are from, it removes the unnecessary step of a user needing to first select the region (or you can just infer the region based on the country selected if needed). Allowing a user to start typing the country they are from will also narrow down the options available to choose from (an advantage over listing all options available in a dropdown list / graphically).

Smashing Magazine wrote an article about redesigning the way countries can be selected (they landed on using a combo box too). They documented their design process for this quite nicely too and is worth reading. There's also a live demo and a GitHub repository.