Yesterday, i saw a great video on youtube.This is the Steve Jobs “Steve Jobs’ 2005 Stanford Commencement Address”
Checkout this great video http://www.youtube.com/watch?v=UF8uR6Z6KLc
This video is worth watching million times. I have never seen such a great video.
If any of you have heard any other great presentation please put the link to that in comments.
Shekhar Gulati 
Good, funny and somewhat inspirational presentation by Guy Kawasaki:
http://video.google.com/videoplay?docid=-3755718939216161559#
I like it.
Check this out..surely, one of the Best Video ever seen..