We just bought our kids their 6th bed, each.
Forget toddler beds, little kid beds, and big kid beds. After the crib, consider buying a full size bed instead.
Discussion
This is so true. We went crib -> Twin-size bunk beds -> full size. I still find my oldest bunking in my youngest daughter's room. I think that deep in our souls, sleeping is a communal act, something which has been lost in modernity. Although sleeping alone does provide me the most vivid dreams.