In what is shaping up as an all-out price war over HDTV sets, several national retailers have announced that they are one-upping Wal-Mart, which recently said that it would be slashing prices of the sets hundreds of dollars in the run-up to the holiday season. Best Buy, Circuit City, Sam's Club, Costco, Target, Sears, and Kmart each announced huge cuts in LCD, plasma, and projection HDTV sets, with several promising special savings on Friday, the biggest shopping day of the year. (Some of the "big box" chains have announced that they'll open at 4:00 or 5:00 a.m. on that day.) Home Media Retailing magazine reported today (Monday) that shoppers are expected to spend $21 billion on consumer electronics this season.