Here is My understanding of the Per Core and Cals
per core is limited so if your server has 2 Quads that is going to be 8 licenses
and per cals it is unlimited so really
best thing is to buy the license with 5 cals and then down grade to 2008 or 2008 R2
Thats the I understand iI got. **and buy far not the smartest rock in the bag**
SQL is now licensed per Core where once it was licensed per socket. but the one thing that has not changed is the server + CAL(device or user) licensing model.
with the per core model you do not need CALs. that is why it is so expensive (1 scoket = 4 cores).
the best for you is the server + CAL model. when i set my up i bought about 5 device licensed and 40 users.
i mix the users and device licenses so if the device is licensed then unlimited users for that device. hoverever if the user licensed then the user can access SQL with unlimited number of devices.
so in your case vCenter is a device then it can use unlimited users. next how many users will be connecting to SQL server? in my case i had 40 as i was also using my SQL server for SharePoint.