Family. Ask a hundred people, and a significant portion will tell you that it's the most important thing in their life. The top priority that they work to support and maintain. I'm firmly in the "Family is Important" camp, although most of my family doesn't share much genetic material with me.
Having gone through a great many changes in the past couple of years, my "family" has also shifted over this time. PG (aka META whetstone) and I are no longer married romantic partners, and are investigating what it means to continue to be important in each other's lives, to be family on some level. S and I keep moving in the direction of growth and integration on a deeper level, and that dynamic is one of the things that feeds me. D and I are finding more ground to share, and staying firmly pointed in the direction of long-term connection and adding value to each other's lives.
Our daughter is a huge focus at the moment. She is struggling with the changes in her family landscape, and we are all trying to help her sort through things. I feel empowered and supported by having so many loving and caring people that are ready and willing to plug in to help her find her way, even as I strive to bring better patience, skills and understanding to the table. My now-ex mother-in-law is someone that's been a parent to me since I was 18, and however the paperwork looks, she and I still have a strong family bond that will continue forward.
The bio family is sort of a non-factor most of the time. They live far away, and are very different people, so the main function they have in my life is to be extended family as possible with our daughter. They moved away when I was about 20 years old, so haven't really been important in my adult life.
Then there's the poly community! These people are like my cousins, siblings, grandparents, aunts and uncles. They provide a broader context for my family construct. Filling in the gaps and creating space that I wouldn't otherwise have access to in my life.
One of the strengths of poly is the opportunity to reinvent the concept of family in a broader context. Don't limit yourself to the genetic pool you crawled from! Family is where you find it, build it, create it.