Starting at 3:30 is his acoustic Whole Lotta Love encore, performed tonight in San Francisco. I recommend watching all the way to the end.
I love the progression starting at 6:06. And 7:54 to the end is really something.
(Video by Suz526. H/t to Hooplamagnet.)
Update: Another video of the same performance with audio that is better in some respects.
Update 8/9/10: Another video of the same performance. This is cut together from several fan-taken videos.