I'm looking forward to seeing the responses here as we are somewhat new to 100 premium. With a comparable MAS 500 implementation, we would recommend 16 to 32 gb of RAM and dual, quad core processors. Licensing woudl be done by user CAL rather than per processor due to the new licensing scheme rolled out in SQL 2012.
On disks, we always recommend 4 logical drives. Each logical drives would be comprised of a separate RAID 1 array. We would go to other RAID technologies if greater space or speed were needed. We would also recommend a SAN array if data storage was going to get large with more than 50 heavy users. Server virtualization helps with fault tolerance and would be recommended as well.
The drives are broken down as follows:
1.Operating System and applications
2.SQL Data Storage
3.SQL Log Storage
4.SQL tempdb storage
The size of each logical drive would vary based upon the projected size requirements for data and application load.
We also create one tempdb for each processor core on the server. This help with speed through put as well.
Note: all this relates to SQL 2005 and/or 2008. 2012 is still undiscovered country for us.