You know the money is back in the Valley when Paris Hilton comes to town. Okay, she's ostensibly in San Francisco tomorrow for a signing of her new book, Heiress. But this would be the appropriate moment, financially speaking, to switch her attentions from Greek shipping heirs to internet moguls. So who's she most likely to be seen with at Slide, tomorrow night? (Before you quibble, no pre-existing girlfriend gets in the way of Paris Hilton.)