TONIGHT'S MUST-SEE

"America's Next Top Model," 5 p.m., CW (digital cable channel 93); and "American Idol," 8 p.m., Fox. Both shows are down to their final three now. The difference is that "Model" is declaring a winner tonight; "Idol" has another week. "Model" takes the final three to a cosmetics photo shoot then trims the field to two. They work a fashion show in Sydney, Australia, before one is named champion. "Idol" last week trimmed LaKisha Jones, a powerhouse who had the misfortune of having much in common with two other strong singers, Jordin Sparks and Melinda Doolittle. Blake Lewis, a good performer having a bad week, joined Jones in the bottom two.Tonight, we learn which two will be back next week for the finals.

"Lost," 9 p.m., ABC. Last week's episode was filled with thunder shocks. Ben admitted he hadn't been born on the island, after all. His dad was brought here to work on the odd project there; eventually, he joined native islanders in killing all the project people, including his dad. He told all of this to Locke — then shot him and left him to die. That's the start of what will reportedly be a tough body count over the next couple weeks. There was more: Juliet told Jack she was reporting back to The Others and said it was only a scam to hold them off. And the show kept toying with the whole "this is Purgatory" notion, an idea that the producers have consistently denied. Things continue tonight as plans begin for a daring attempt to destroy the Others. First, Charlie must try a mission that could leave him dead.

OF NOTE

"Price is Right Million Dollar Spectacular," 7 p.m., CBS. Bob Barker will continue to host new daytime episodes of "The Price is Right" until sometime in June, then settle into retirement. For primetime viewers, however, this week offers a two-part farewell. Tonight, Barker hosts his final evening show, with contestants spinning the wheel for a shot at $1 million; tomorrow, CBS profiles Barker and his long career.

"Secrets of the Dead," 8 p.m., PBS. Six Irishmen were imprisoned in Australia for eight years. Then their colleagues disguised their ship and tried a daring rescue. That story is retold and studied in this documentary.