I posted a simple AppleScript for launching menu bar items to GitHub. This is how I maintain an obsessive degree of control over the order of my menu bar items, since you can’t drag to reorder the third-party ones, and controlling the launch order is impossible from the Accounts → Login Items preference pane.
It also significantly decreases my boot time when I just want to get the computer on to do one thing, and not wait for ten things I don’t need yet to start up.
To prevent apps from “helpfully” adding their menu bar tools to my Login Items, and to avoid having to open up Preferences and delete the same handful of them repeatedly, I just disabled Login Items completely.
In Finder, I went into Username/Library/Preferences, found loginwindow.plist and renamed it to loginwindow.plist.bak in case I change my mind later. Then I created a folder, and named that the same thing. This prevents the operating system from writing any data to it.
When you reboot and go to System Preferences → Accounts → Login Items, it will be completely empty and no apps will be able to add themselves there at all. Forever. Or until you put that loginwindow.plist file back the way it was.
No more junk, no more trips to the Accounts preference pane to delete things I didn’t ask for, and Launch.scpt can do its job while I get a glass of water if I do want all of those menu bar apps running after all.