What is the difference between Apple Remote Desktop / Remote Management / Remote Login / Remote Events and Screen sharing?
You are correct, VNC is a simpler version of Remote Desktop (note: Remote Desktop uses the VNC protocol in addition to adding a lot more features)

Remote Desktop offers more management features; ability to black out host computers screen, push updates, file transfers etc (think TeamViewer but by Apple).
http://www.apple.com/remotedesktop/

VNC doesnt have any of these options, its just a simple way to access a remote screen.

Remote Login allows you to SSH to a remote computer (command line - you dont see the remote desktop)

eg You may want to run a command on a remote computer, you could connect using VNC and open terminal or instead you could remote login via SSH and run the command without actually interacting with the screen of the remote computer

Updated to include @Wheat Williams notes below