Rue McClanahan (otherwise known as Blanche, "the sexy one," from The Golden Girls) recommends Whiskers (235 East 9th Street; 979-2532): "They have everything I need -- from veggie dog biscuits to organic catnip." Super pet-store chains are the way to go -- if you know what you want, how much you need, and where to find it. But if you crave personal attention and want someone knowledgeable about pets, Pet Stop(1572 Third Avenue, between 88th and 89th Streets, 410-4100; 564 Columbus Avenue, between 87th and 88th Streets, 580-2400; and 3605 Riverdale Avenue, Bronx, 718-549-5900) has everything from posture-correcting food bowls for bigger dogs to a new cat litter made of 100-percent dried corn that flushes easily and won't harm your cat if eaten. Gourmet cookies, canine ear wipes, and even digestive-tract conditioner line the shelves. Prices are reasonable; every seventh bag of food is half off.