For a quick resource and reference, I did a quick Google search on "a beer a day" to see what kind of articles I would find on beer and health. There were a few interesting finds.
This report titled Three Beers A Day Keep The Doctor Away mentions some of the benefits of drinking beer.
Here is one from The Telegraph, stating that a Pint a day is the recipe for health.
This article in About.com is worth checking out as well.
In a nutshell... beer is good for you. It is natural, non-fat, and packed full of nutrients. (Sounds good, huh?) But the warning is not to drink too much (of course).
Myself... I try to have at least two days during the week when I don't drink. Why? I guess it helps me realize that I don't need it and that I really only enjoy it. I limit the weeknights to just one beer generally, and save the weekends for enjoying the further benefits of beer.