We at Channel Cloud Consulting think one of the best examples for how Virtual Private Cloud (VPC) will advance the tipping point to pure Public Cloud and away from in-house data centers is CSC’s BizCloud.
CSC is certainly not the only game in town for VPC.  AmazonRackspaceAT&T and others offer a VPC.  But CSC is perhaps the most robust, at least according to Gartner
CSC does a great job of contrasting Private and Virtual Private Clouds.  CSC is built on VMware’s vCloud reference architecture which means that the seamless private-hybrid-public feature set is in place.
It’s a simple story, for garnering all the advantages of the ‘Utility’ of Public cloud:
  1. Off-load capital
  2. Load Balancing to avoid over or under capacity
  3. Lower cost ‘as a service’ makes IT faster, better, cheaper
  4. Consistency and better SLAs
While at the same time providing the advantages of private cloudS
  1. Seamless Cloud Connections 
  2. Security and Isolation
  3. Network controls
Here’s a compelling graphic on CSC on their BizCloud VPC

The power of the VPC lies in the fact that for the first time, enterprise IT can consider an alternative to in-house deployments or owning equipment for Tier 1 and TIer 2 (core production) workloads rather than seeing the cloud as a place where peripheral workloads (BCDR, test dev, etc.) or off-loading peak capacity can take place.
It is this option “we no longer need a datacenter” that in our view will drive the tipping point to the public cloud and the tsunami that will force CIOs to re-evaluate the role of the in-house datacenter.
The tipping point is closer than you think.

- Channel Cloud Consulting