The Bible deserves the first spot on your reading list.

After that, consider some of the following books:

Leadership Development
Visioneering Andy Stanley
Courageous Leadership Bill Hybels
Spiritual Leadership J. Oswald Sanders
Good to Great Jim Collins

Discipleship
The Life You've Always Wanted John Ortberg
Ruthless Trust Brennan Manning
Spiritual Leadership J. Oswald Sanders
Renovation of the Heart Dallas Willard
Whatever Happened to Worship? A.W. Tozer
The Unquenchable Worshipper Matt Redman
The Pursuit of God A.W. Tozer
The Jesus I Never Knew Philip Yancey
Growing True Disciples George Barna

Evangelism
Becoming a Contagious Christian Bill Hybels
Out of the Saltshaker Rebecca Manley Pippert
The Case for Faith Lee Strobel
The Case for Christ Lee Strobel
Surprising Insights from the Unchurched Thom Ranier
Beyond the Box Bill Easum and Dave Travis