My pennyworth: I do wine labels as well! I make bottles with thick walls - so the polys are actually like if you cut a bottle in half: it has a thickness rather than a skin. Then I put a volume inside for the liquid. I colour the liquid to roughly what white/red wine looks like. And then I colour the bottle glass to roughly what it looks like without wine inside it. After that you have light passing through several object layers, just like in the real world.
In a studio, a photographer spends most of his time trying to kill reflections, so I would keep them to a minimum personally. Diffuse is nice, but really glass doesn't give diffuse reflections in a bottle - it's more a slight bump because the glass is cheap. If the highlights are too smooth they don't look real, even in top class advertising shots.
One of the keys to rendering bottles is to keep the raytracing value high for both the glass and the liquid shaders as well as in the render room (a Mark Bremmer tip) - around 14 or 16 or more if you have time. Then you get quite good depth in the colours because the calculations read through the object instead of bouncing off it.
Brian's suggestion is good - a better one is to put a white light behind because you can control how much light blasts through the bottle and wine. Messing about with its position left and right can give you nice results as well. For a whisky a pack photographer might put a lump of gold card behind the bottle so the front lights reflect back a richer yellow in the centre of the bottle etc etc
So you can pretty much use the Carrara standard shaders out of the can - it's all adjustable in the lighting
