Nurture vs. Nature?

OK- if we can remember back in our psychology classes (maybe even science) they talked about kids' behavior either being formed by nature (just how they were born), or from nurture (how we train them to be).

Our kids are total opposites. One is independent, strong willed, smart. The other is dependent, easy going, and funny. Now, I realize that some of that is due to birth order. I still wonder if we have influenced it some in the things we say and do.

What do you think plays a bigger role? Why? Is it equal? They say most of who we are is formed from birth -5yrs. Do you think we, or our kids, can truly change negative behaviors?