Darth Vader would make dog meat out of Chewie
Yoda and The Emperor would be a tough fight, but I believe Yoda would eventually emerge triumphant. C3PO wouldn't have a look in, although he could theoretically be rebuilt ad infinitum and therefore outlive everybody, but, in a fight, I would say the winner would be....Yoda
Unless we are talking about a pre-cocaine A New Hope Leia dressed in a ROTJ bikini (in which case she would distract obi-wan and then blast him) , it is obvious to me that Obi-Wan would win this 'battle' hands down.
I love Han, but Luke has the force. Luke would win.
So, my choices are as follows:
Vader
Yoda
Obi-Wan
Luke