metaluns is a great way to get a lot of I/Os, but at the expense of a bit more complexity, also if you don't need a lot of ESX capacity you might end up with more space than what you need or sharing those disks with other non-ESX guests. It might be easier to just create smaller raid groups and LUNs for your ESX hosts, maybe use Raid 1/0 if you need the extra I/Os.
I am current using Meta Luns. We have 3 raid groups made up off 6 disks in a raid 5 .
with 12 x 110Gb Luns per a raid group. then meta-luns are 3x 110 luns together to create a 330Gb luns.
we end up with 12 x 330Gb Luns , with a max 15 VM's per a LUN
This take into account a reasonable VMFS volume size and number of VM's per a volume
If you look at EMC testing they always use meta luns made up of raid gorups uisng 6 disk raid 5.