Here are a few handy properties and methods that are found on the System.Environment class:
Current OS: System.Environment.OSVersion
Current working directory: System.Environment.CurrentDirectory
string[] of drives on the machine: System.Environment.GetLogicalDrives()
Version of .NET app is running under: System.Environment.Version
Current machine name: System.Environment.MachineName
Newline symbol for the current environment: System.Environment.NewLine
Number of processors on the current machine: System.Environment.ProcessorCount
Full path to system directory: System.Environment.SystemDirectory
User name application is running under: System.Environment.UserName