Philo Beddoe vs. Jack Wilson in Any Which Way You Can. Sorry, no clip.
Most of the fight scenes from the movie The Raid: Redemption
http://www.imdb.com/title/tt1899353/?ref_=nv_sr_2
or these.... (It's so many!!)
The fight scene in "They Live" between Rowdy Roddy Piper and Keith David is epic.
Anytime a mention of 'best fight', you have to include Bruce Lee at the top. No one on screen had the charisma with fighting skills he had.