Brewman,
Don't forget that medical is automatically deducted from your salary as well. As soon as you get here and start registering for everything that the government requires, it will be 100 dhms here 100 dhms there, which adds up quickly. You will also need a car w/ insurance, make sure you calc that in too. Plus, if you take a furnished apt, even though it's furnished, it's sparesly furnished and you will want to add your own stuff on top of that. That will add a monthly expense as you outfit things your own way. You won't be getting any flying pay for several months, so take that into account. If you get the EPC card, that's a small monthly amount as well. They will also take out your portion of the provident fund. If you travel, especially back home to the states, that will add up very quickly as they are not the cheapest tickets home. If you buy TV's, computer, etc, that adds up. I brought some stuff over and bought a ton of converters, which saved, but the price of the converters adds up w everything (U.S. TV's don't work over here by the way, different region for the TV).
Just some things to add to your thought process. Lots of hidden fees here that you never think of until you get here and then go "Where the hell did my paycheck just go?"