FORMERLY a distant fourth design destination after La Cienega, Beverly and Robertson boulevards, La Brea Avenue is poised to mount a more serious challenge with the arrival of new retailers and the renovation of old favorites. The strip now extends southbound from the modern lighting store Rewire Gallery near Oakwood Avenue to the relocated and expanded glass house Retro Gallery, south of Olympic Boulevard. The most dynamic section, however, is between Oakwood and 2nd Street. Accessory Preview opened last summer with Asian decorative objects made from wood, clay and shells. Across the street, the Francophile spot Bourgeois Boheme and the Italian modern Eccola have enlarged their spaces and added traffic-stopping window displays. On the 100 block of North La Brea, across the street from longtime locals Fat Chance, East Meets West, Svenska Mobler and Silho, you'll find the contemporary furniture store Seva and the Buddhist home boutique Silk Roads, two newcomers in the massive complex housing Barclay Butera Home. Between 1st and 2nd streets, more contemporary furnishings can be found at Homework, Landon Cole and the minimalist Vioski. Last stop? Novecento Antiques has Deco, neoclassical and postwar Italian Stilnovo designs at the kind of prices that make La Brea a time- and money-saver.