My friends from Houston, Texas make some some of the loudest and most exciting acoustic music you will ever hear. If you don't believe me, just listen to this: Pressed for Time. As Wayne and Garth would say, "We're not worthy, we're not worthy!"
My personal all time favorite pipe band is/was the 1998 Victoria Police Pipe Band from Australia. They won the World Championships in Grade I the same year we (the Hamilton Pipe Band) won it in Grade III. They had the purest sound and some of the best music I have ever heard produced by a pipe band. To hear them live in Scotland that year was truly amazing.
This is the organization that sanctions and helps to organize and officiate the many highland games competitions in the Eastern United States (including my home state of Texas, oddly enough). Their website is a great resource for all things related to pipe bands and bagpipe competition in this part of the world.
One of the top Grade III pipe bands in the Eastern United States, the Grandfather Mountain Pipe Band has been host to the Grandfather Mountain Highland Games near Linville, North Carolina, for over 30 years.