Excellent script. However, I don't understand the reason for the test in:
IF CAST(LEFT(CAST(SERVERPROPERTY('ProductVersion') AS VARCHAR),1) AS INT)>8
I understand that the ComputerNamePhysicalNetBIOS property did not exist prior tp SQL 2000 but your test would return a 1 for SQL 2008.
I assumed your code was for SQL 2005 or higher since you query sys.databases and use sp_send_dbmail.
Thanks again for a very usefull script.