Holiday cards, like fruitcakes and other expressions of the season, say something about the senders. For politicians and celebrities with delicate images to guard, choosing one poses special challenges. Should the seasonal message be somber? Provocative? Soothing? Or, like George Bush’s card, which numbered a record 1 million and cost an estimated $370,000 for postage, ubiquitous? This year bigwigs around the globe ran the gamut. –By Harriet Barovick THE BUSHES The message of the unseasonal oil painting by Shanghai-born American artist Zhen-Huan Lu? Serene and diplomatic. But who is the White House pianist? DAVID LETTERMAN With a fitting fantasy of a walk down the aisle with J. Lo, this year’s woman of his dreams, Dave’s Late Show card blithely avoids the holiday completely. CANADIAN M.P. Member of Parliament Jean Guy Carignan’s card, featuring Yasser Arafat, sparked an uproar. He said it reflects his wish for harmony in the Middle East: “I am in favor of peace and justice.” LORETTA SANCHEZ The Congresswoman got laughs and kudos in Washington for her parody of the Master-Card “priceless” ads, featuring her family, with cat Gretzky, in a red Thunderbird. THE BLAIRS Breaking from tradition, the Blairs dressed casual, projecting calm, cool assurance.