When I get a bottled beer, I always ask that it not be poured into a glass, which would then have to be washed, using energy and nasty chemicals. Plus, I trust the people at the bottling facility to produce a clean bottle more than I trust Pedro, the minimum wage dishwasher to get the glasses clean.
I got a vasectomy, thereby relieving the landfills of excess used condoms, but I haven't come across any impact studies on the ecological benefits of two less condoms per year, but I figure every little bit counts.