IATA calls it Myanmar (scroll down the list). So perhaps we should adopt the 'travel industry-standard' and call it Myanmar?
I vote for burma. Although the official name is myanmar, there are many reasons to choose burma instead. Discussion on the topic can be found here on Wikipedia. Wikipedia itself settled for Burma after a lengthy discussion, and so do various major news outlets. It mostly boils down to the question if the military governments decision to change the name should be considered legitimate or not.