Full details leaked on new ESX 3.1.0 and VC 2.1.0 features:

virtualization.info has a scoop on the official new features that will be in the next major VI 3 release later this year.
Quoting from virtualization.info:

• Solid State Drive (SSD) boot support
  As initially discovered last month, VMware will make available a special version of ESX Server (mentioned with terms like ESX Lite and Embedded ESX) for OEM vendors, to be installed into bootable Solid State storage devices (flash drives, etc.). This option will allow creation of ESX Server hardware appliances for easy jumpstart, granting smaller form-factors and improved reliability.
  Dell, IBM and possibly other vendors will offer this option at announcement time in Q3 2007.
• DMotion
  Unofficially introduced with ESX Server 3.0.1, in its first version DMotion is a special VMotion operation only capable of moving running virtual machines from an ESX Server 2.5.x host to a new ESX Server 3.x., without shared SAN LUN mandatory requirement.
  In ESX Server 3.1 this capability will be extended, allowing hot migration of running virtual machines between ESX 3.1 hosts through the Ethernet cable.
• Patch management system for host and virtual machines (UpdateManager)
  ESX Server 3.1 will finally introduce an automated patch management system called UpdateManager. This solution will be able to update both host itself and virtual machines (both Microsoft Windows and Red Hat Enterprise Linux).
  UpdateManager will feature security backup before patching and automated rollback if something goes wrong.
• VMware Consolidate Backup (VCB) and VMware Converter integration
  VirtualCenter 2.1 will now allow restoring VCB images with an integrated version of VMware Converter.
• Server consolidation advisor
  VirtualCenter 2.1 will expose a server consolidation assistant able to analyze which physical machines should be converted in virtual ones, and where to move existing VMs among available hosts.
  (note that with this feature VMware is further extending competition with PlateSpin, covering both features with PowerRecon and PowerConvert)
• Guest OS disaster recovery capability
  VirtualCenter 2.1 will be able to recognize a failure inside a virtual machine and restart it through VMware HA module.
• Power saving capability (Distributed Power Management)
  VirtualCenter 2.1 will introduce a new resources utilization analysis feature, able to verify when a physical host can be powered off, VMotion-ing its virtual machines on other hosts without impacting performances.
• Support for Cisco Discovery Protocol (CDP)
  VirtualCenter 2.1 will be able to recognize and use CDP to discover physical and virtual network topologies.
  It stays unconfirmed if ESX Server 3.1 will already expose new virtual network architecture, allowing 3rd party virtual switches, as it will be announced by Cisco CEO at VMworld 2007.
• Support for 10Gbit Ethernet network cards
• Support for TCP/IP Offload Engine (TOE) network cards
• Support for network load balancing algorithms
• Support for 200 hosts and 2000 virtual machines
• Support for 128GB RAM per host and for 64GB RAM per virtual machine
• Support for SATA storage devices
• Support for N_Port ID Virtualization (NPIV)
• Support for VCB over iSCSI SANs
• Support for IPv6 in virtual networking