I will echo the rave reviews for the Costco bag. I upgraded from an el-cheapo rollaboard to the Kirkland (Costco's brand name) bag and I love it. It has all of the gee-whiz features of the Travelpros or B&Rs, at a fraction of the price.
Costco has terrific customer service, too. Their return policy rivals Nordstrom's. Back in January 2003, I bought a digital camera to take on deployment to Iraq. With the sand and stress, the plastic catch to the battery door. After I returned from the Gulf in June, I took the camera back to Costco to see if they could hook me up with a repair. They took the camera back and gave me a brand new one free!!!! No questions asked!
The bag is great - you won't go wrong with it.