Second the back (facing Las Vegas Blvd) bar area at Mon Ami Gabi. I have eaten there solo both at the bar and at a table. Good food, lively atmosphere, and the water show from the Bellagio across the street.

I would also highly, highly recommend Bouchon in the Venetian. Really outstanding food. They, too, have a bar with menu service, but you can sit at a table overlooking a nice patio area. This is also a great place to go for a wonderful breakfast.