My vote would be the Spring/Cypress Jersey village area...
All are in the NW part of town and the airport can be accessed by both FM1960 and the Sam Houston Tollway. The cost residence isnt that much more expencive, its a little higher because the area is generally MUCH better then the inner city(rent maybe, cost of living is still decently cheap...food, gas, etc...)
I lived in Jersey Village and going on the Tollway(they have EZ tag acess which is a prepaid tag which allows you to pass through a toll station without having the stop and pay toll), it took me about 15-20 mins to get from my house to the IAH FBO's where i used to work.
Spring would be a short drive up 1960 either down I-45S or keep taking 1960 and enter the back way down Lee Rd near the Fex Ex FBO.
Also Humble is a decent area, just the approach glidepath going into RWY 27 and 26L/26R is right below and all everyone ever does there is complin about how loud the planes are and "why cant they just move them somewhere else"...
Though if you dont mind, Humble is a really easy area to get to the airport as well, and the residence there is decently priced. thats more NE side of houston off US-59
My best bet would be the NW side(Spring, Cypress, Jersey Village) But the best for getting to IAH out of the 3 would be Jersey Village or Spring, since both ways to get to the airprt are pretty much on a single road/freeway
I hope this helps, If you have any questions feel free to ask. I have lived in the Houston NW area for over 23 years. So ill be happy to answer any questions you have
Greg