KEVIN Costner has made a string of memorable films, from the convoluted thrills of No Way Out and high adventure in The Untouchables, to the gentle Bull Durham and the award-winning Dances with Wolves. Indeed, you'd be hard pressed to name a bad Costner movie . . . if it wasn't for Revenge (Pearl 9.45 pm, Original Running Time 120 mins), a ponderous love story that fails to captivate. Costner plays a newly retired navy pilot who visits old pal, Tiburon Mendes, (Anthony Quinn) an ageing powerbroker whose life he once saved. Mendes also happens to be an ex-gangster which you'd think would put Costner off messing with his young wife (Madeleine Stowe). But no, soon Costner and Stowe are enjoying an illicit quickie and surprise, surprise, Mendes ain't happy. Revenge is part of Pearl's Be My Valentine campaign to raise money for the Children's Cancer Foundation. Donations have now reached $197,000, almost twice the target figure. NARROW Margin (World 9.30pm, ORT 97 mins) may not have the clout of Costner but it's a better movie than Revenge. Gene Hackman is outstanding as an assistant district-attorney escorting a frightened murder witness (Anne Archer) through the Canadian Rockies. Archer witnessed a murder, and a bunch of heavies who work for the gangster who set up the killing are out to stop her testifying (got that?). There are some great action sequences - particularly the climactic scene on top of the train - which makes up for occasional weaknesses in the story. MURPHY Brown (Pearl, 7.35 pm) fans should not miss tonight's episode when she finally gives birth after her water breaks on the air. The FYI crew take turns to stay with Murphy (Candice Bergen) throughout her lengthy labour. Corky's reaction to her shift with the imminent mother is to rush home to stock up on birth control pills. MANDARIN Moonlight The Legend of Tian Yuen Mountain (World 11.35pm, ORT 119 mins) is the story of Law, the head of a research group, who in 1956 is sent to a labour camp for 20 years after being accused of being rightist. Law's story is contrasted with that of Ng, a drifter who becomes Commissioner of the Regional Committee at the time Law is jailed. STAR Plus is making much of its new series The Wonder Years (7.30 pm). Admittedly the show, which follows the memories of a man looking back fondly to his early teens in the late 1960s, was an award-winner, but it's hardly new to Hongkong. LATE night viewing is headed by Krishna Shah's Rivals (Pearl 1.20 am, ORT 103 mins) the story of a child who plans to murder his mother's new husband. Decidedly offbeat. If they can stay up late, country music fans will love Baja Oklahoma (Pearl 2.25 am, ORT 105 mins), a charming film about a Texan barmaid (Lesley Ann Warren) who dreams of being a songwriter. Look out for music stars Billy Vera, Willie Nelson and Emmylou Harris, and one Julia Roberts just prior to winning her first real acclaim for Mystic Pizza and Steel Magnolias. PRIZE for the most nauseating ad around must go to a certain muesli bar favoured by one of those impossibly radiant mums and her sickly-sweet kid, and all to the cringe-making tones of another ankle-biter singing: ''I'm feeling a little hungry Mum, I've got a rumble in my tum.'' Pass the sick bag, Alice.