I took my bile in to the LBS yesterday to get a rack/panier installed on it and the guy doing the wrench work was sort of astonished that I hadn't had any problems out of my wheels. At first I thought he was just trying to see me something, but after our discussion I was convinced that he was legitimately concerned.
He said that my wheels were actually pretty good for your average rider, but with my weight I would have done better to pick a bike with better ones, but not to go out and purchase anything but rather to wait until my wheels starting giving out and that he'd rebuild them for the price of some better spokes and no labor.
After all was said and done, they had installed my rack/panier, trued my wheels for free, and threw in a couple of reflective leg bands for free... best shopping experience ever.