I always perfer the response in front of the history of a thread.  I usually
have read the other messages in order, and it's a pain to page down through
every message to se the few lines someone has added.  If I need the history
refressher, then it's there, but if I don't, I don't have to weed through it
so see if there is any reason to read on.

I am accustom to this behavior in all the email packages I have used, albeit
only three (OE, DaVinci, and Notes).