VMware is to announce the official release of vSphere 4.1 tomorrow. One great option for SMB Clients is vSphere Essentials Plus.
VMware vSphere Essentials Plus—This kit includes all the features of vSphere Essentials, plus High Availability and Data Recovery to automatically recover your data and restart your virtual machines in the event of system failures; with vMotion technology, now you can completely eliminate planned downtime during server maintenance.
I also mananged to find a list of features, a main one being support for passthrough USB, can it really be true? Anyways go here for the complete list of BETA features, its possible that not all will make it in the official release, I will post again after vSphere 4.1 is officially released.