READERS' PICK: Has anybody here seen my old friend John? Can you tell me where he's gone? Well, you won't find the assassinated president, but you will certainly find numerous representations of his toothsome image at the Shelter Cocktail Lounge. Imagine, for a moment, if Joey Heatherton (or Nancy Sinatra) had stolen into your parents' suburban Phoenix house on a hot night in 1966, slipped lysergic acid into their Harvey Wallbangers and ordered them at gunpoint to redecorate the living room. This roughly describes the interior of the Shelter. A mélange of '50s and '60s memorabilia (with a heavy emphasis on Kennedy festishism) combines with incredible martinis, vintage pinball games, lava lamps, friendly bartenders and a persistent bullfighter subtext to make the Shelter the hottest bar in Tucson. The clientele is as varied as the décor: blue-collar workers, downtown hipsters and curious college students, all enjoying the Turner Classic Movies, black velvet paintings, mustard-yellow booths and flashing JFK teeth. And remember: If you don't go to the Shelter, the terrorists will have already won!