Oddly, or not so oddly Paramount is the only studio in Hollywood so I hear. Burbank has a ton, Van Nuys still has at least one I believe, there are even studios now in Valencia (small but they're there). Here is an interesting link http://www.insidehollywood.info/index.php?pg=address-film-studio&mn=sl
Yup, Burbank. I live here. And it's not just major studios, just drive down the street and there are lots of hole-in-the-wall film, photo, and production companies everywhere.