By Erin Richter
October 31, 2003 at 05:00 AM EST

WHY HIM An obnoxious but loyal Everybuddy, he gives oomph to small parts…

WHY NOW …like in ”Runaway Jury” and ”Scary Movie 3.”

No leading man is an island. He often has a best friend or insufferable foil — a part Jeremy Piven has played for 17 years. ”[My whole life’s been] ‘Here’s your audition, dance for whitey, do the role, not get celebrated, audition again,” says the Chicago native, who’s made a career of supporting roles in ”Ellen,” ”Serendipity” (with real-life pal John Cusack), and ”Old School.” ”But I’m not serving fries at Wendy’s, so it’s good.” After ABC’s ”Cupid” ended five years ago, Piven — who’s not as sour as he sounds — focused on film. Now he’s playing a fast-talking consultant in ”Jury” and an annoying anchorman in ”Scary 3,” and he’ll next protect First Daughter Mandy Moore in ”Chasing Liberty.” After that? ”I’ve written my first script; it’s inspired by my father,” says Piven, 38. ”But do I want to be that guy, who talks about my screenplay?” So he opts for the exotic: ”In five years, I’d like to be in Bali, picking fruit from a luscious tree.” Just steer clear of the bitter kind.