War
you want to go with landscape mode due to wide field of view, if you go portrait it is like having a single large screen. 99% of the triple monitor setups go landscape for better FOV.
In portrait mode there's a whopping 1920 dots vertically. That raises a couple of questions: Out of the box, does AH fill the screen like in one screen situations? I mean, is there more to see up and down wise like a chased enemy up front or the lowest cockpit gauges? Or does the game use the increased resolution to draw distant dots with more pixels, making them look more like aeroplanes than dirt spots on screen?