Honestly, I don't agree with you. Here is my top 5:
Cedar Park - My pick to win it all. They have made the finals at Grand Nationals and won the 4A Contest in 2001.
Vandegrift - A close second. I have only seen them perform one time but they were very good.
Friendswood - They have gotten second three times: 2003, 2005, and 2009. I don't think you can count them out of possibly medaling.
Dripping Springs - Performed a great show in 2009. Could they repeat?
Waxahachie - Won the Honor Band competition this year and have improved greatly in their marching abilities.
Other notables:
Connally HS
Poteet HS
Hendrickson HS
Vista Ridge HS
Aledo HS
Dawson HS
Hays HS
Roma HS
Legacy HS
I am sure there are others I am forgetting. This contest could likely be the most competitive in 10 years. Several of these bands could probably make the finals at the 5A contest next year.