Great quote from a Forbes article today: “I only ever hire ‘A’ players for me and my companies. If I hire ‘A’ players, they will hire ‘A+’ people below them. If I hire ‘B’ players, they will hire ‘C’ players below them. ‘A’ players don’t get threatened by better people below them; ‘B’ players do.”
This was from an article called The Best Advice I've Ever Received about Hiring Talent.  I agree with this completely! I always focus on hiring smart people, and encouraging them to hire even smarter people.  It works like magic, because smart people thrive on being around other smart people.  In any group, the slowest person literally slows down progress for the team.