Big Boy Bed or Crib???

Now that we are expecting this next new little boy, we are torn between whether to get another crib (what I'm leaning towards), or get a big boy bed for Radcliff. I can see the benefits to both. One thing I do know is, Rad looooves his crib. It's his little domain. He can play in that puppy for a looong time, perfectly content, after waking up. Would it totally uproot his little system by getting a big boy bed? If we do decide to make the transition, I think it would be fun to do it when the baby comes and get a really cool, fun bed like the one above to make that whole time frame of somebody new and foreign coming into his life, cramping his style, seem more fun to him ;) Do any of you have any thoughts in regards to this? I'd love your input on what has worked well for you family, if you've gone through the same thing!  The Bedz 'R' Us bed above can be found here! How cute is it!?