e4 best by test according to bobby fischer.
Anyway, in my opinion there is no best opening. I think you should read this website to get yourself set with an openings reportoire.
http://www.chesspublishing.com/content/repert2.htm
http://www.chesspublishing.com/content/repert.htm#AM
I have heard that the Scotch Gambit is good but after reading articles and Forums I realize that it is not that great. What would you recommend?