MUST-SEE TV! Tonight on "Charlie Rose," a smackdown between Joe Scarborough and Paul Krugman. After arguing over the debt on their blogs, they're taking it to the airwaves, for the full hour. Tapes today on Charlie's legendary set at Bloomberg HQ in Manhattan. Airs 11 p.m. on WNET in NYC, and WETA and WHUT in D.C., and 200+ other PBS affiliates.