esxi 5.5 optimal RAID and diskgroup configuration

Hello,

I am sure this topic has been beaten to death but I will still go ahead and ask it again.

Currently we have a setup of 1 MD3220i and 3XR815 esxi4.1 (free) servers, 2 switches. We are going to add another MD3220i and upgrade the esxi to 5.5  since esxi4.1 has 2TB LUN limitation, it wastes quite a lot of space when we create multiple VM's. The configuration is used to host medical records on multiple instances of Sybase SQLAnywhere database's running on multiple Windows VM's.

Our workload is about 40% Reads. The new MD has 24 X 1.2Tb 10k SAS drives. We are planning to move all our VM's to the new MD and use the old MD as backup. Maybe reconfigure all the drives on old one to better take advantage of larger LUN size. 

What would you suggest as RAID configuration (10, 5, 50) and disk grouping for maximum performance for the 24 X 1.2 TB array?

Thanks in advance.