A great place to stay in Mendoza is a boutique hotel El Aguamiel. It's situated in the middle of a small vineyard and has views of the Andes.

This is the view from our room. I would guess that the other rooms (I think there are only six) have similar views.

We spent one afternoon relaxing on our private patio (with a bottle of Malbec, of course) and watching the reflection of the sunset on the Andes.