There's Bucca di Beppo, which was mentioned before. Hard Rock is kind of small and loud and I wouldn't recommend it unless you're a real Hard Rock Cafe fan. There are also some asian restaurants, a Tony Roma's, a Mexican Restaurant, a MiniBrewery type place, a Wolfgang Puck restaurant (I believe it's one of the Grill type places, not the REALLY expensive variety), and a Saddleranch which is right by the park entrance (that's really popular with people I know). I am personally fond of The Daily Grill and there's a Bubba Gump's seafood place opening soon (sadly Gladstones is gone).
For less expensive fare, Citywalk also has a sort of "food court" on its second level which has places like Subway, Tommy's, etc. There's also cheaper stuff not in the "food court" including: Starbucks, a pizza place, Coffee Bean & Tea Leaf, Jamba Juice, a pretzel place, a hot dog place, and a crepe place.