Can a DBA function without rights to the Server OS?

I see posts often regarding questions for what rights should be granted and to whom with regards to SQL server.  On this post I am going to address what rights should a DBA have to the Server itself based on the following question recently from the MSDN Forums:

What is a DBA/sa prevented from doing if not a local admin on the SQL Server?

If you read the above post, you will see that my answer is different from start to finish on the thread.  At first I would have said that a DBA needs to be a Local Administrator on their server, but this really doesn't stand up to the whole idea of least necessary permissions, that as a DBA I enforce myself.  I happen to be a Local Administrator on my servers at my job, but that really probably is overkill, and could be reduced.  So what rights would a DBA need to a SQL Server at the OS level?

This is determined and or dictated by the definition of the role of a SQL Server DBA.  As a SQL Server DBA, there are certain things that I expect to be able to see and or do, and that I would argue belong within my realm of responsibility.  A short list of these tasks would be:

1. Monitoring Performance Counters
2. Managing Database Files
3. Managing SQL Server Updates and Service Pack Installations
4. Viewing System Event Logs
5. View active Processes on the Server through PerfMon or TaskManager
6. Start and Stop SQL Services
7. Monitor Available Disk Space

Now arguably, the easiest way to accomplish the above is to make the DBA a member of the Local Administrators group on the SQL Server, and I would never argue against this practice, it is after all the DBA's job on the line if the server goes down from a mistake they made as a local administrator by goofing with something they shouldn't have.  I personally like having the rope to hang myself, but I can also use that same rope to climb out of a valley in the event of an emergency as well.  I personally know my limits, and I know when to involve my server team members with looking at a problem.  This may or may not be due to my past experience as an NT4 and Windows Server 2000 Administrator, it was something close to 8 years ago, but I know where to draw the line of responsibility.

So where do you sit on this subject?  I am interested to know if you are a DBA that doesn't have Administrator Access to the Windows Server, how you created permissions to do the above.  How would one go about granting the individual rights required to be a DBA without being a Local Administrator?  I can only figure out how to grant a subset of the above, but as I said previously, I am not a Windows Administrator, MCSE, or any other sort of subject matter expert when it comes to security outside of the SQL Server database engine itself.