It's hard to think green all the time. Like when you're standing in Best Buy looking at all the electronics equipment, trying to decide which TV to buy. You want to choose something that is environmentally sensitive, but the salesperson gives you a blank stare when you ask. There is no signage (other than Energy Star) to tell you that a company is a stellar enviro-citizen or that they are dumping their waste in third-world countries.
Thankfully, researchers are out there working to help you make informed decisions. I try to remember what authors Ellis Jones, Ross Haenfler and Brett Johnson wrote in "The Better World Handbook." It's a great little book that teaches you ways to make a difference without being an all-out activist. It's about influencing with your purchasing dollars.
Another great resource is Green America's Responsible Shopper, which "provides you with the real story about abuses by well-known companies, gives you actions to promote corporate responsibility, and helps you green your life and world."