TONIGHT'S MUST-SEE

"The Biggest Loser" finale, 8 p.m., NBC. The show is down to its final four now, all of them from the Black Team of early rejects. Bill, 40, is the only guy. He's a gregarious Long Islander who has lost 130 pounds, 39 percent of his original weight. Isabeau, 21, is from Franklin, Tenn., and feels her weight has stymied a singing career. She's lost 81 pounds, 27 percent. Hollie, 28, is from Phoenix, a former cheerleader. She's lost 64 pounds, 25 percent. Julie, 34, is from Jacksonville, Fla., married for 18 years. She's lost 58 pounds, 27 percent.

"Independent Lens: An Unreasonable Man," 9 p.m., PBS. Democrats see Ralph Nader as an ogre whose third-party candidacy put George W. Bush in office. This documentary lets both sides argue that at length. First, though, it vividly reminds us of Nader's immense impact. This is the man whose fierce determination led to auto-safety reform and a revolution in consumer protection.

OF NOTE

"Clash of the Choirs," 7 p.m., NBC. The four surviving choirs perform. Then viewers decide which three will be in Wednesday's final sing-off.

"NCIS," 7 p.m., CBS. Here's a plot twist that was previously used on "Crossing Jordan": A family has asked that there be no autopsy, out of respect to its Muslim religion.

"Bones" and "House," 7 and 8 p.m., Fox. Here are two excellent reruns. In the first, a killer seems to be copying cases from Brennan's book; in the second, a 6-year-old girl has had a stroke and her 8-year-old brother is hitting on Cameron.

"Snowglobe" (ABC Family) 8 p.m. A charmingly offbeat Christmas movie.

"The Unit," 8 p.m., CBS. Jonas wonders if a British agent is working for the other side.

"How the Grinch Stole Christmas," 7 p.m., Cartoon Network. Here's another chance to see one of the truly great TV specials.

"Boston Legal," 9 p.m., ABC. Alan defends Clarence in a foreclosure case; also, Denny defends the firm's claim that it's pro-environment.

"Saving Grace" season finale, 8 p.m., TNT. As played (superbly) by Holly Hunter, Grace has seemed both exciting and tortured. Now we see why, in a fiercely emotional hour that brings childhood memories.

Make a difference. Donate to The Advertiser Christmas Fund.