Some people celebrate their 40th anniversary with diamonds or extravagant parties. Patricia Field is commemorating her 40th year in retail with a new boutique. Marking a return to the East Village after closing her seminal 8th Street store in 1996, the two-level Bowery shop is a veritable This Is Your Life--style retrospective of the fashion icons costume-design career. Graffiti by street artist De la Vega, trophies from the sets of Sex and the City and The Devil Wears Prada, and a neon sign from her shuttered Hotel Venus outpost make lively set dressings for playful garb such as Heatherette chiffon frocks ($336), Michael and Hushi halter dresses ($380), and Fields own Girls (and Boys) Just Wanna Have Fun--themed togs. And for shoppers (and drag queens) in need of a pre--Happy Valley makeover, theres also an on-site hair and makeup salon.