I'm with the group that says drink in moderation. I had an occasional glass of wine while breastfeeding both my kids and they are both healthy and smart. Matter of fact, when I came home with my first, some friends dropped by with a six-pack of my favorite beer and let me taste test each one that was opened (since I had been VERY good and not had any alcohol during pregnancy).
Remember that the medical establishment really can't put a guideline out there for alcohol use during pregnancy or breastfeeding because they can't do testing on those groups of people; so they have to say "none" for safety.
I'd stick to a glass or two of wine on an infrequent basis. And, as one grandmother pointed out to me, if just a little gets in the breastmilk, what you get is a sleepy baby, which is also sometimes a nice thing. As noted in another post, plenty of our moms were recommended a glass of wine, and we turned out just fine.
Also, I was told to drink just before feeding the baby, not just after. The alcohol doesn't go immediately into the milk and that gives a longer time for it to get out of the bloodstream before the next feeding. Plus, as noted, it helps relax you for the letdown.
Sushi, raw eggs, rare meat, raw oysters, etc. are dangerous because of the chance of salmonella poisoning. If you eat it and get sick, it's a pain. If you eat it while pregnant and get sick, they are worried about the fetus (don't remember the particulars). If you get sick while breastfeeding, worst case scenario is that you have to pump and dump while sick to avoid transmitting the salmonella.
All of that being said, remember that plenty of Japanese women eat sushi while pregnant and breastfeeding. My midwife even said it was fine to eat when pregnant as long as I went to a reputable restaurant where I had gotten quality sushi before. Same thing goes for the other stuff.