Now that I think about it, I don't think I've watched any Trek in over a year!
Been watching other shows, I guess (in the scifi arena, LOST and Supernatural on DVD immediately spring to mind, plus a run-thru of Farscape last year)
I think the last time I watched any Trek, it was a run-thru of the final arc to the finish of DS9. So I'll go with
What You Leave Behind.