Today, VMware released vSphere 5.5. Lots of people in the community have already been writing about the new features.
There is special whitepaper released by VMware that goes in detail about all what is new in this release.
VMware-vSphere-Platform-Whats-New.pdf
At this blog article from the technical marketing team you find a short list of the things changed and new and also the link to the whitepaper mentioned above:
a-summary-of-whats-new-in-vsphere-5-5
The full documentation can be found at: