Ok, my first reaction: Whew! As in, "Whew, it's over..." :-)
Seriously, though, I appreciate the really useful discussion. Which has two readings, doesn't it: "I appreciate the (entire) discussion, which was really useful", versus "I appreciate the useful subset of the discussion (in contrast with the useless bits). I meant the former.
That's all from me for now. I'm looking forward to seeing how the discussion progress.