I think so. I see sustainability as the fully committed, hard-core stuff, and green living as the path to get there.
Another thing I tend to ask to help me know whether I"m making the best choice possible is "What are we sustaining?" Are we trying to sustain unhealthy foods or agricultural systems, or social systems that disconnect us from each other or the things that matter to us? "Green" products can't bring us any more satisfaction than other products. Our choices need to not only be sustainable, but also sustain us on a personal or spiritual level.