Almost all enterprises are virtualising. Based on surveys, the majority of large companies consider building a private cloud a core strategy. While the direction makes sense, be careful about getting too caught up in the hype of building a perfect private cloud. A cloud service requires a self-service (or non-manual) interface, and some form of usage metering, or even chargeback.
Not every IT organisation needs a fully self-service cloud experience, and many SMB organistions see little value in usage metering. They simply want to deliver services faster. For them, a 70% private cloud is absolutely good enough (ahh the old 70/30 rule!)
There is still exceptional value in virtualising your resources, automating how the resources are allocated to meet demand, automating provisioning based on standard service offerings in a published service catalog. But you may want a person in the middle of the process. Or you may want to route the pure self-service requirements to your favorite external cloud provider rather than build your own.
How you carve it up is fine, it all comes down to business requirements, return on investment, and future strategy (including the potential to evolve to external cloud providers in the future). How far you go is your decision.
So while most enterprises may consider private cloud their goal, and vendor hype is going to skyrocket on how to reach that goal, I think that organisations will be more than happy with a less than perfect cloud.