defaults write com.apple.finder ProhibitGoToFolder -bool true ; killall FinderNot only will the menu item be gone, but the Command-Shift-G shortcut that brings up the Go to Folder dialog will no longer work.
Want to get it back? Just run this command:
defaults write com.apple.finder ProhibitGoToFolder -bool false ; killall FinderNote that this command does not prevent access to the user's Library folder; if you press the Option key while displaying the Go menu, you'll see Library show up as an option, between Home and Computer.

