When I go to Houston and have a dreaded early morning flight my hotel of choice is the Sheraton IAH. (Plus I'm an SPG member.)

This is a thread with reviews of the place:

http://www.flyertalk.com/forum/showt...&highlight=iah

I have never had a problem there, as a Platinum got upgraded almost every time and the airport shuttle runs with good frequency.

If you are a member of a particular hotel program you may want to look at their properties as well.