One other advantage to Costco is that they extend the warranty on TVs and computers to 2 years from date of purchase.
I have a 32" TV we bought for the bedroom in October of 2009. It took a dump last month, and the manufacturers warranty is long over. Costco took over and had me take it to a repair shop where it's currently sitting. So far they've replaced the motherboard, and now are ordering a power supply board for it. Costco is handling the repair, and calls me every couple of days with updates. They've been absolutely fantastic the way they've handled it. A big
to Costco.