I came across an interesting article in the Autumn issue of University of Toronto Magazine. It indicates that John A. Cunningham, a behavioural scientist at U. of T., has come up with new criteria for defining how much alcohol consumption is too much.
You can measure your own drinking habits against these criteria by taking a short five minute survey at checkyourdrinking.net.
The survey asks about the amount of alcohol you consume, and compares it to averages for others of the same age and sex. On an annual basis it also reports how much you spend on alcohol and how may hours you are under the influence of alcohol. Lastly, based on the amount of alcohol you consume, it also gives you your chances of suffering various negative consequences which are specified in some detail.