Just to add a little to this thread.
The 2TB limit is an absolute limit meaning that snapshots are inclusive in the limit.
I would suggest you look at something like a 1.8TB lun meaning you have 200GB - 512B of snapshot space when backing up etc..
If you require more than the 1.8TB you can use volume sets from within the OS or extents which currently on ESXi5 allow for a 16TB volume.
It all gets a bit messy if you need volumes over 1.8TB but it's doable.. The other option is to put the data behind a SAN, you can then present it as an RDM!!
