I highly recommend cabling up all the 3PAR host ports available to you from day 1 and evenly distributing your hosts across them from the beginning... try to keep it even and symmetrical... storage Feng Shui.
Its better to have 8 ports at 10% utilization vs 4 ports at 20%, or 2 ports at 80%.
Ports have 2 limiting factors, GB/s is the one everyone pays attention to, but they also have limits to how many IO/s each port/card can do... this is often not published either. Someone already mentioned the limit of how many initiators per port you have, and I would like to go further to point out that each storage port has a limit of how many queued IO it can support - see the graph below, taken from the 3PAR-ESX5 best practices doc:
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This is the total queue depth per "target port"... each host connected to a port may have a per Lun queue depth of 32 or 64.