RE: Equallogic and VMware, Multple VM's in one DATASTORE???
It really depends on the IO load of the VMs and the SAN configuration. If you are using RDMs or VMDK a really great tip is to create a virtual SCSI adapter for each VMDK/RDM. This will improve performance.
One thing on the snapshot, you do not have to do a full restore of a LUN in order to leverage snapshots. It's true using the GUI restore option and entire LUN would be rolled back. However, you can put a snapshot online, add it as a datastore, then restore a single VMDK OR mount that VMDK to another VM and restore a single file if desired. ASM/VE 3.x also allows a single VM restore from a snapshot. (or replica)
For heavy IO Windows servers (i.e. SQL, Exchange) we recommend using the MS iSCSI initiator inside the Guest to connect to array volumes. This allows all the features of the ASM/ME on those volumes. (Enhanced MPIO, snapshot, and replication)