First, are you wanting leadership or motivational?
Leadership
ANYTHING By John Maxwell. Ken Blanchard, Bill Hybels, Jim Collins, Stephen Covey, Dale Carnagie to name a few that are good.
Motivational
ANYTHING By Zig Zigelar, Tony Robbins, a few of the above guys and NICK VUJICIC will slap you around a bit too.
Don't know where your faith is, but there are some REALLY good biblical based books out there as well. I've been to the Willow Creek Leadership Summit a few times and it has always been really good. They have all sorts of high profile leaders that they are talking with and interviewing, both believers and non believers, all for leadership.
https://www.willowcreek.com/about/
I got more if you're interested.
