BY JUD COST

Looking as mean and trim as they ever did, X was the perfect bicarbonate of soda for all that rich and greasy holiday food-not to mention a palliative for last week's hellacious assault on the senses of unsuspecting fans by Mercury Rev at San Fran's Independent club: a barrage of nonstop, industrial-strength strobe lights coming at you from all angles in all colors and unpredictable oscillations.

X, on the other hand, stuck to their music in front of a packed house that kept each other warm in the moderate-sized, barn-like atmosphere of Slim's on a chilly Saturday night. With only a few skimpy strings of (non-flashing) Christmas lights draped across their amps and a set list dotted with the occasional Xed-up yuletide surprise ("Santa Claus Is Coming To Town" and a wonderfully sloppy take of Chuck Berry's "Run Rudolph Run"), Exene Cervenka, John Doe, Billy Zoom and D.J. Bonebrake have become a holiday tradition every bit as anticipated in San Francisco as Phil Spector's Christmas album blaring out in the upscale Union Square shopping emporiums.

"We love playing for all the crazy people in this town, and if you consider yourself one of them, this is for you," barked Doe before launching into "The New World," whose recurring line "It was better before before they voted for what's his name" has taken on a whole new meaning after the political turmoil of the new millennium.

It was a throng old enough to remember the Fog City boy/girl vocal-tandem predecessors to X, Grace Slick and Marty Balin of Jefferson Airplane, even if many of them wouldn't admit it. The Clash's line "No Elvis, Beatles or the Rolling Stones in 1977" dies hard among some. But a patchouli-doused, top-hatted, Haight-Ashbury greybeard danced among the tattooed, leather-jacketed punks, a few of whom might have seen an early Northern California appearance by X at the pre-expansion version of tiny East Bay club (50-capacity) Berkeley Square back in 1980.

Now living in Oakland, former Rain Parade guitarist Matt Piucci was here tonight with his 14-year-old son Nick in tow to let the kid soak up a little Tinseltown history. "I took him to see Brian Wilson and Iggy last year," shouted Piucci over the din. "It's like teaching him about Bach and Beethoven."

"It's a career that's been really good to us, and we enjoy playing, and we don't suck, so we're going to keep doing it," the deadpan Doe told the San Francisco Chronicle's Aidin Vaziri earlier in the week when asked about the band's 31-year run. Dead-accurate, romping versions of X classics like both sides of their first Dangerhouse single "We're Desperate"/"Adult Books" along with early gems "Johny Hit And Run Paulene," "The Hungry Wolf" and "We're Having Much More Fun" ("We'll whap your yappin' dog!") more than proved the case of the singer whose honest, workingman's lead vocals are the perfect foil for Cervenka's unique harmonic ear.

By the time they'd rocketed through the autobiographical "Los Angeles" at a little past the one-hour mark, Christmas fatigue was kicking in. It was either stick around for the finish and risk an attack of asleep-at-the wheel on the 50-mile drive home down the fog-bound 280 freeway, or split now and live to see X play Xmas again at Slim's next year. It was a tough choice but the right one.