I just shut down my MacBook Pro 4.1 2.4Ghz Penryn last week, outside of the odd restart from Apple, this is the first time the machine has been fully off since 2008

there is no need to shut down your Mac, and there is absolutely no benefit. OS X performs routine self maintenance, if you shut the computer down the system wont complete the tasks, if you sleep the OS will run the routine's on the next wake up - it`s time to let go of Windows
And the Penryn, well having more than earned it`s dues, it now moves to the standby system, with the new Air being primary, well until Apple release a Pro that is designed to run SSD from the ground up