Alcohol, despite being harmful to you when consumed in excess, is actually beneficial to you in moderate quantities. Research has shown that alcholic beverages such as wine help to control or reduce your blood pressure which in turn reduces the risk of heart attack or stroke:
“One to two glasses of wine a day either has your blood pressure come down, or stay the same.” Dr. Richard Stein, M.D. from the American Heart Association.

However Dr. Stein goes onto say that increasing your consumption above these levels can produce the opposite effects :
Once you get up to 4 or more glasses, or the equivalent of that, you start to notice an increase in blood pressure with an increase in heart risk that outweighs the benefit of wine,” said Dr. Stein. Alcohol reduces the risks of blood clots and helps raise levels HDL-cholesterol which mops up the bad LDL-cholesterol and sends it to the liver.

Diabetes and obesity are key factors in the development of heart disease. “Regular consumption of 1-3 alcoholic drinks per day of any type of alcholic beverage reduces the occurence of type-2 diabetes by 40-50%.” The Wine Diet, Roger Corder.

Studies have also shown that drinking more than the recommended level of alcohol may result in weight gain due to its empty calories.

So the conclusion here seems to be moderation. Less than 4 glasses a day is recommended. The healthier the wine, such as the wines listed on this site, the less you need to maximise the health benefits while at the same time minimising the risks associated with drinking too much alchohol.

Drinking wine with food is recommended, as this slows the absorption rate into the blood stream and allows the liver to cope without risking blood poisoning. This is also the safest way of drinking a glass of wine if you have to drive (staying of course within the legal limits!). It is not recommended to drink any wine at all if you’re driving, especially on an empty stomach.