The dining situation at Disney's Hollywood Studios is embarrassingly bad and needs to be rectified. I suppose the entire park needs a general face-lift, but that's a conversation for another thread.
Besides The Hollywood Brown Derby, which is typically quite good, none of the other table service options offer particularly good food. 50's Prime Time Cafe and Sci-Fi Dine-In Theater provides a wonderful atmosphere and entertainment. All Disney fans should experiences theses two places at least once, because the settings are so unique. Children usually love these two, and if you stick to basic food, the meal will be decent.
I have always been pleasantly surprised by Mama Melrose's, but it consistently receives mediocre reviews on these boards. Maybe I have been lucky.
The counter service landscape is even more barren. There isn't a single location my family enjoys, making a quick lunch considerably more difficult than it should be. I have read that Starring Rolls serves a few sandwiches that are tasty, but I haven't tried them yet.
The best suggestion I have is to leave the park. As others have said, Epcot and its surrounding resorts are just a boat ride or walk away. The BoardWalk, Beach Club and Yacht Club all have lovely restaurants, including Kouzzina, Cape May Cafe and Captain's Grille.
Hope this helps, and good luck!