Go ahead, laugh all you want. But Sentimental by TV's terminally perky Kathie Lee Gifford is a sweet surprise. She delivers 10 pop standards (''Over the Rainbow,'' ''Hey There'') with effortless grace and, best of all, with no pretense. Deep she's not, which is why things wear a little thin halfway through. But in small doses she delivers a happy kind of thought-free pleasure. B

