My personal preference is on the top, but not to delete previous messages unless they no longer apply to the current discussion (Thread creep? We ain't got no stinkin' thread creep!).
That way you can scroll down to refresh your memory, if necessary
>Is is proper etiquette to include your comments at the top of a message you are replying to, or at the bottom?
"You don't manage people. You manage things - people you lead" Adm. Grace Hopper
Pflugerville, between a Rock and a Weird Place