”I have a major career decision to make,” Dennis Hopper announces as he digs into his suitcase. ”I’m doing Late Night With David Letterman. Should I wear the blue shirt” — he holds it up against his natty Armani suit — ”or the yellow shirt?” Once one of Hollywood’s most notorious rebels — he bummed around with James Dean in the ’50s, dropped acid with Jack Nicholson in the ’60s, and spent the late ’70s on a psychedelic binge — these days the 55-year-old actor gets his kicks from duds, not drugs. ”I’ve mellowed,” he concedes. ”I’ve calmed down. I even voted for Bush.” Hopper has appeared in some movie milestones — Rebel Without a Cause in 1955, Giant in 1956, Easy Rider in 1969 — but his career sputtered to a stop in the ’70s. It wasn’t until 1986, when David Lynch cast him as a deranged killer in Blue Velvet, that Hopper reclaimed his fame. ”I’ve been typecast as a psycho because of that movie,” he says, ”but I don’t mind. They’re interesting parts to play.” He plays one again in Paris Trout, but this time with a twist: ”He’s a much more realistic psycho. This one really could have existed.” As for the shirt, he chose the yellow one.