TONIGHT'S MUST-SEE

"Doctor Who" season-opener, 5 and 6:30 p.m., Sci Fi Channel; episodes rerun at 7:30 and 9 p.m. Ever since the mini-budget days of 1963, "Who" has offered witty British science fiction. It's gone through more than 700 episodes and 10 people playing the Doctor. Christopher Eccleston, who had the role last season, made him intense. David Tennant, who arrives tonight, makes him jaunty. Both benefited from the delightful Billie Piper as Rose, a shop girl turned time-trekker. Tonight, she returns home safely, but he (in his new body) is comatose. Evil aliens are right behind; there are modern special effects, plus the wit of old. In the 6:30 p.m. (and 9 p.m.) episode that follows, the Doctor and Rose visit cat people in the future.

OF NOTE

"Celebrity Duets" finale, 7 p.m., Fox. This show has dumped wrestler Chris Jericho, gymnast Carly Patterson, actress Lea Thompson and others. Now the winner is announced.

"Ghost Whisperer," 7 p.m., CBS. A ghost is fascinated with Melinda and threatens to harm her husband.

"Grey's Anatomy," 7 p.m., ABC. Here's a quick rerun of last Thursday's season-opener. Diahann Carroll and Richard Roundtree play Burke's parents, arriving at an embarrassing moment for Cristina.

"Hannah Montana," 8 p.m., Disney Channel; preceded at 7 p.m. by a rerun. Dolly Parton guests as one of the few people who know that teenaged Miley Stewart is also pop star Hannah Montana. Tonight, Miley has boy troubles and Parton gives advice. It's a weak story, salvaged by the amiability of Miley Cyrus (who stars), Billy Ray Cyrus (her dad on the show and in real life) and Parton.

"Close to Home," 8 p.m., CBS. A psychiatrist has been killed and his wife is charged with murder. She chooses to defend herself.

"Numb3rs," 9 p.m., CBS. This is the second half of a story about a schoolteacher and her teen lover. Desperate to get him back, she takes Megan (Diane Farr) hostage.

"Law & Order," 9 p.m., NBC. The body of a slain soccer mom is shown on the Internet.