For lunch, the best food is at the Grand Lux Cafe at the Venetian. It does have a Vegas coffee shop atmosphere but the food is wonderful and the menu is enormous. It's run by the Cheesecake Factory.
Battista's is a nice choice for a casual Italian dinner. It's all-inclusive, including all the wine you can drink.
If you want something a little nicer, Emeril's (MGM) is fabulous and not as outrageously priced as many. Reservations a must.
QL