I wonder if homebrewing ends up being better for the environment than commercial beer. The economy of scale would seem to suggest that it's not. However, it's worth noting that many bottles can be reused indefinitely--just brew your own beer, buy an inexpensive capping machine and add new caps. E-Z-cap (or lever cap) bottles require no new metal caps, and less fuss, yet are considerably heavier (Grolsch is the most famous beer that comes in these). A desire to put those heavy, solid bottles to another good use was actually one of the main reasons I started brewing.
I can't arrive at an opinion about whether homebrewing is better for the environment overall, but it's definitely a rewarding hobby, and the beer is considerably healthier than most commercial beers. Contrary to the opinion of a recent Slate article, it doesn't require that much geeky fanaticism, either, although some take it to that level. For someone who just wants to have fun and drink beer, it is a relatively simple process. If you want to make an exact copy of a rare Belgian Trippel, it becomes more complicated.
On the subject of kegs, I was filled with a sense of righteous environmental indignation when my alma mater, Brown University, banned them from dorms in a moment of uncharacteristic prudishness. The idea was that kegs encourage binge drinking, but I bet that a 24 pack of Natty Ice does the same thing, and creates more waste.
