vSphere 5.0
Auto Deploy - enables diskless ESX hosts with PXE boot and centralised patching
Support for Apple products - Xserve servers running OS X Server 10.6 as a guest
Storage DRS - VM placement and load balancing based on available capacity and I/O
Profile-Driven Storage - SLA based storage provisioning and compliance monitoring
Thin Provisioning API - array monitoring, reclamation and pause when out-of-space
Storage Awareness API - discovers storage array topology, capabilities and state
Web Client - access vSphere from any Web browser anywhere in the world
vCenter Server appliance - run vCenter Server as a Linux-based virtual appliance
ESXi Firewall - stateless engine restricts access to specific services
ESXi only - thinner architecture, more secure footprint, and streamlined patching/setup
Update Manager - upgrade 4.x "Classic" to 5.0 ESXi and simultaneous host patching
Virtual machine format 8 - 3D graphics, USB 3.0 devices and EFI BIOS
Larger virtual machines - up to 32 vCPUs and 1TB RAM per virtual machine
Memory - swaps to SSD to minimise performance impact when memory is low
VMFS5 file system - unified block size (1MB) and increased performance and scalability
Software FCoE - requires NICs that support partial FCoE offload
Storage I/O Control - supports NFS to provide better performance for I/O intensive VMs
Array Integration API - supports NFS with Full File Clone and Reserve Space features
Network I/O Control - per VM controls, host replication traffic and 802.1p Tagging
Distributed Switch - supports NetFlow, Port Mirror and LLDP
High Availability - increased scalability and performance, and simplified setup
vMotion - supports higher-latency networks and multiple NICs for better performance
Storage vMotion - improved performance and support for snapshots/linked clones
DRS/DPM - ties "Agent VMs" (such as vShield) to ESX hosts that will not be moved
Data Recovery - e-mail reports, exclusion of swap files and improved performance
iSCSI multipathing - configured from vCenter rather than command line

vSphere 4.1
Storage I/O Control - set storage quality of service priorities per virtual machine
Storage Performance Reporting - for improved tuning and performance troubleshooting
vStorage APIs for Array Integration - offloads tasks to arrays to improve performance
vStorage APIs for Data Protection - supports Windows 2008 VSS application quiescing
Network I/O Control - set network quality of service priorities per flow type
Memory Compression - enhance memory overcommit and increase performance
DRS Host Affinity - restrict placement of virtual machines to a subset of hosts in a cluster
HA enhancements - Healthcheck status, Operational Status and optimised DRS interaction
FT enhancements - DRS interaction, versioning-control and improved logging performance
Improved performance - for NFS, vMotion, Storage vMotion, virtual desktops and vCenter
Cloud scalability - more virtual machines and hosts per vCenter Server than ever before

vSphere 4.0
Host Profiles - standardises settings across multiple ESX hosts
Linked Mode - provides visibility across multiple vCenter Server instances
VM counters in Perfmon - provides accurate guest performance analysis
Orchestrator - automates vSphere tasks using a powerful workflow engine
Fault Tolerance - provides continuous availability to any application
Storage vMotion - now with reduced resource consumption and vCenter management
Data Recovery - provides agent-less disk backup and recovery of virtual machines
HA Maintenance Mode - suspends failover actions during maintenance operations
vShield Zones - enforces network security policies across virtual machine zones
VMsafe - enables security products to work within the ESX host rather than guest OS
Hot Add - supports adding CPUs/memory and adding/removing PCI devices
64-bit VMkernel and Service Console - provides greater scalability and performance
Distributed Power Management - puts hosts in standby to reduce power consumption
Virtual Disk Thin Provisioning - enables VMs to utilise storage on an as-needed basis
Paravirtualised SCSI adapter - offers greater I/O throughput and lower CPU utilisation
Distributed Switch - spans many ESX hosts significantly reducing ongoing maintenance
Private VLANs - restricts communication between VMs on the same network segment
Network vMotion - enables tracking of the networking state of a VM as it moves
3rd Party Distributed Switch - supports the Cisco Nexus 1000V virtual switch
Pluggable Storage Architecture - supports EMC PowerPath multipathing software

vSphere Hypervisor
Provides a simple and easy way to get into virtualisation at no cost
32GB vRAM entitlement
No centralisation management and automation

vSphere Standard
Provides server consolidation and no planned downtime
8-way SMP and 32GB vRAM entitlement per CPU
Thin Provisioning, Update Manager and vStorage APIs for Data Protection
vMotion, High Availability and Data Recovery

vSphere Enterprise
Provides powerful and efficient resource management
64GB vRAM entitlement per CPU
Virtual Serial Port Concentrator, Fault Tolerance, Hot Add and vShield Zones
vStorage APIs for Array Integration, vStorage APIs for Multipathing and Storage vMotion
Distributed Resource Scheduler (DRS) and Distributed Power Management (DPM)

vSphere Enterprise Plus
Provides policy-based datacenter automation
32-way SMP and 96GB vRAM entitlement per CPU
Storage I/O Control, Network I/O Control, Distributed Switch and Host Profiles
Auto Deploy, Storage DRS and Profile-Driven Storage

vSphere Desktop
Designed for licensing vSphere in VDI deployments
Includes all the features of Enterprise Plus with unlimited vRAM entitlement
Licensed based on the total number of powered on desktop VMs

vCenter Server
Foundation
Centralised management for up to three vSphere hosts

Standard
Provides large scale management of vSphere hosts
Linked Mode enables a common inventory view across multiple instances of vCenter Server
Orchestrator streamlines and automates key IT processes

Heartbeat
Fails over to a standby vCenter Server in the event of a loss of service

Essentials packages
Essentials
Licenses for 3 physical servers (up to 2 processors each) and vCenter Server Essentials
8-way SMP and 32GB vRAM entitlement per CPU
Thin Provisioning, Update Manager and vStorage APIs for Data Protection

Essentials Plus
vMotion, High Availability and Data Recovery