PowerShell – Get Special Path

###############################################################################
## Get-SpecialPath Function (should be an external function in your profile, really)
##   This is an enhancement of [Environment]::GetFolderPath($folder) to add 
##   support for 8 additional folders, including QuickLaunch, and the common 
##   or "All Users" folders... while still supporting My Documents, Startup, etc.
#
FUNCTION Get-SpecialPath 
{
   param([string]$folder)
   BEGIN {
      if ($folder.Length -gt 0) { 
         return $folder | &($MyInvocation.InvocationName); 
      } else {
         $WshShellFolders=@{CommonDesktop=0;CommonStartMenu=1;CommonPrograms=2;CommonStartup=3;PrintHood=6;Fonts=8;NetHood=9};
      }
   }
   PROCESS {
      if($_){
         ## Eliminate the options that are easiest to eliminate
         if($_ -eq "QuickLaunch") {
            $f1 = [Environment]::GetFolderPath("ApplicationData")
            return Join-Path $f1 "\Microsoft\Internet Explorer\Quick Launch"
            ## Test WshShellFolders first because it's easiest won't throw an exception
         } elseif($WshShellFolders.Contains($_)){
            if(-not (Test-Path variable:\global:WshShell)) { $global:WshShell = New-Object -com "WScript.Shell" }
            return (([string[]]$global:WshShell.SpecialFolders) -split " ")[$WshShellFolders[$_]]
         } else {
            ## Finally, try GetFolderPath, and if it throws, change the error message:
            trap
            {
               throw new-object system.componentmodel.invalidenumargumentexception $(
                  "Cannot convert value `"$_`" to type `"SpecialFolder`" due to invalid enumeration values. " +
                  "Specify one of the following enumeration values and try again. The possible enumeration values are: " +
                  "Desktop, Programs, Personal, MyDocuments, Favorites, Startup, Recent, SendTo, StartMenu, MyMusic, " +
                  "DesktopDirectory, MyComputer, Templates, ApplicationData, LocalApplicationData, InternetCache, Cookies, " +
                  "History, CommonApplicationData, System, ProgramFiles, MyPictures, CommonProgramFiles, CommonDesktop, " +
                  "CommonStartMenu, CommonPrograms, CommonStartup, PrintHood, Fonts, NetHood, QuickLaunch")
            }
            return [Environment]::GetFolderPath($_)
         }
      }
   }
}

Get-SpecialPath("quicklaunch")

Reference: http://poshcode.org/5988