VMware Disk Maximums

edit - VMFSv3 only...

Because I'm always forgetting the Logic in the VMware Maximum Storage capacity for a datastore, LUN and VMFS volume.

Max Extent size 2TB minus 512B
Max VMFS size 64TB minus 512B
Max Number of Extents per Volume 32 (32 x 2TB = 64TB)

I was told by several people they prefer 500GB LUNs to allow the smaller block size. Then join the LUNs via extents in your datastore. Of course this gets to be a pain to setup if you're trying to configure a very large datastore.