Hey Von. Well.......... Ive poked around on other boards that have CoC games and most of them are all arkham, boston, or another north american city.
As you maybe know im running a D20 set in Buenos Aires Argentina and would warmly recommend you to take the game to a location you have connection to, as i have to South America. I think that in the end as GM it will make the description of places and behavior of NPC's more realistic and time correct for the country/city the action will develop. On the other hand you can allways take people to another dimension, make PC's explore time drowned cities below the outer peel of the Earth or a long time forgotten tunneling project in the outskirt of the city you choose.
You say middle east is interesting and yes it is, i would love to jump on that train
-DH