I'm interested in acquiring a snake. However, I don't know jack about them

I want either a harmless constricting snake or just a plain harmless snake, as there are little children and pets around here. However, I also would like a snake at least several feet long, but nothing overly large. What snakes do you guys recommend for novice snake owners? I would also like to know what I need for a good setup for the snake...thanks in advance