LOS ANGELES (AP) — William Shatner is back as a shrewd, unflappable travel expert in his latest TV commercial for an online company. Shatner returns as the priceline.com Negotiator in a new ad campaign that launches Sunday, with Kaley Cuoco-Sweeting ("The Big Bang Theory") again playing the travel pro's daughter. Another longtime passion is horses, which he rides competitively and which help him keep fit.