USH is a very small park, I usually finish seeing everything at lunchtime, or just after, so I usually eat at CityWalk.
I always go to Bubba Gump or Johnny Rockets because of the price. But if you're not from the area, Hard Rock Cafe might be fun.
In the park I like Mel's Diner. It has a nice theme and usually some entertainment right outside. You might even get to see Lucy, Marilyn, or Groucho Marx walking by.
Gru's Lab looks like fun! It wasn't there last time I visited.
You might check out this blog post:
http://www.sandytoesandpopsicles.com/orange-county/california-theme-park/super-silly-fun-land-universal-studios-hollywood/
They ate at Gru's Lab and this is what they got: