The greatest influence on my walk with Jesus has been Oswald Chambers. This is my 17th year of going through My Utmost for His Highest.
I've gone through Destined to Reign by Joseph Prince (4 times), Morning and Evening by Spurgeon, and The Heart of the Father.
But Chambers is the one I go back to year after year because he gets me focused on the details of how to be one with our Shepherd. No other man or woman has had anywhere near the impact on my life as he has.