Cordoba

Depends what kind of honeymoon you are looking for.

I stayed in Mina Clavero for a few days in October and it was great.  It was is a little town surrounded by rivers and the Cordoba sierras.  The rivers were down when we were there, but I think in the next month or two there will be more water.

you can easily hang out and do nothing there, stroll around or take excursions to the mountains and other things like that.

Also, I've heard Villa Carlos Paz is a fun place to stay - although it is more of a city.  It is right near a lake though.

I also went to Villa General Belgrano, but that was for the beerfest.  There were tons of people there and I had a great time and thought the town was really cool.  Has a european feel to it.

There are also town farther out on the route to Villa General Belgrano but I cannot remember the names of them.

Hope that helps.