The basic premise of this hilarious relationship comedy might be old hat, but in the hands of producer Judd Apatow (“Knocked Up”) and writer-star Segel, the well-earned belly laughs are tempered with a poignant touch. (How many movies can you think of where the couple's break-up happens in the nude?) Segel, Bell, Brand, and the rest of the cast are superb, as is Mila Kunis, the flirty resort employee who just might make forgetting Sarah Marshall a possibility for the heartsick Peter. Finally, a spry comedy that hinges on painful truths about love and sex (lots of it) we can all relate to.