How to manage Windows startup?

Startup locations

HKCU refers to HKEY_CURRENT_USER
HKLM refers to HKEY_LOCAL_MACHINE

HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKCU\Software\Microsoft\Windows\CurrentVersion\RunServices
HKCU\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce
HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run

HKCU\Software\Microsoft\Windows\CurrentVersion\Run
HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows
(In right-pane, Value named "Run" & "Load")

HKLM\Software\Microsoft\Windows\CurrentVersion\Run
HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices
HKLM\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce
HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnceEx
HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit

C:\Documents and Settings\All Users\Start Menu\Programs\Startup
C:\Documents and Settings\{Username}\Start Menu\Programs\Startup