But if you changed water into wine, would you get drunk from it?

Well, the intoxicating properties of alcohol are chemical rather than magical, so I would guess that yes, you could get drunk from transfigured booze.

Though it would be really cool if you could transfigure one kind of food or drink into another, while retaining the properties of the original. There's a diet aid for you: transfigure your nice, healthy salad into a bowl of chocolate mousse, but still get the salad calories and nutrition.

Since overweight wizards do exist, I presume that trick doesn't work. :-)