Strictly from a health standpoint everything I've read suggests that 2 glasses per day for men is "ideal" from a healthy heart standpoint. More than that the benefits are outweighed by the negatives and less than that the heart healthy benefits are just not significant enough. My source for this info: the Harvard men's health guide, which is the output of numerous men's health studies conducted by Harvard and other research centers. Other sources I've read support this but I cannot recall them specifically. Women benefit most from 1 glass daily.
From an enjoyment standpoint I find 1/2 to 1 bottle a "nice" amount to drink, especially during the course of an entire evening.
So health wise you are doing yourself no good, but from a life's enjoyment standpoint you are in the sweet spot. Hope that helps a little.