You are not going to like this answer and neither did I.
When I am on a maintenance program, I can get away with a drink or two now and then. "Get away with" is the operative term, because the bottom line is simple and straightforward: alcohol is not healthy; alcohol causes fat retention; and alcohol impedes fat burning.
From the article below which I highly recommend to drinkers who diet, here are the facts:
"Instead of providing you such "permission" it is useful instead if you consider:
On fat loss programs, drinking alcohol is not recommended at all because alcohol suppresses fat oxidation and adds unnecessary calories to your diet, which either displaces nutritious calories or erases your caloric deficit.
For lifelong maintenance, it is recommended that if you choose to drink, that's fine, but only if you do so in moderation (1-2 drinks a day is considered moderation according to most health authorities).
Daily drinking is not recommended as part of a fitness lifestyle, because daily drinking can become habit forming. It is preferable if you can limit drinking to weekends, holidays and/or special occasions.
Try and ALWAYS be cognizant of the calories that are added to your diet through alcohol and above all else know how many calories are in your drinks."
Contrary to popular belief, it is not so much that the added alcohol calories are stored as fat, but rather, that alcohol reduces fat burning. Some evidence for this comes from research carried in the American Journal of Clinical Nutrition. Eight men were given two drinks of vodka and sugar-free lemonade separated by 30 minutes. Each drink contained just under 90 calories. Fat metabolism was measured before and after consumption of the drink. For several hours after drinking the vodka, whole body lipid oxidation (a measure of how much fat your body is burning) dropped by a massive 73%!
All that said, I do "treat" myself on special occasions with a cocktail or two. Rarely, I will get together with friends or family for an outing and really pour it on. Even then, I select as low calorie alcohols as are available and never mix them with sugar, e.g., regular margaritas are out of the question. I also do it knowing that regardless how "good" I am, alcohol is bad if you want to stay lean. I am not anti-alcohol. I am simply saying there is a price to pay for drinking it and sometimes, rarely, I am willing to pay it. However, I never drink alcohol when I am trying to drop into a very lean state.
For more information, you will find an excellent article on drinking and dieting here: http://www.hornetjuice.com/best-alcohol-drink-diet.html
Train hard; diet harder.