A useful booklet shows 1000 acts of Sunnah of the Prophet Muhammad (peace be upon him). It contains different situations i.e. waking up, going to the bathroom, performing ablutions, using sewak, wearing shoes, wearing clothes, going out and coming back home, going to the mosque, athan, iqama, praying at night and post-prayer sunnahs.
Author: Khaled Al Husainan - Khaled Al-Husainan
Publisher: http://www.rasoulallah.net - Website of Rasoulullah (peace be upon him)
A book on how to develop Khushoo in prayers, rulings on Khushoo, the means of developing Khushoo, knowing the advantages of Khushoo in prayers and etc.
Author: Muhammad Salih Al-Munajjid
Publisher: http://www.islamqa.com - Islam : Question & Answer Website
What are the Conditions of Du'aa? Merits of Supplications? Manners of Making Du'aa? Mistakes in Du'aa? Why invocations not Answered? This series answer those questions and other topics.
Author: Khalid Aljuraisy
Reveiwers: Muhammad AbdulRaoof
Publisher: http://www.alukah.net - Al Alukah Website
A nice discussion of some important points needed by those callling to Islam
Source: http://www.islamhouse.com/p/1243
The Choice - Islam and Christianity: Two Volumes, By Ahmed Deedat, An excellent book discussing Islam and Christianity in the light of Holy Quran and the Sunnah.
Author: Ahmed Deedat
Truly & Falsely Jesus In the Bible
Author: Saleh Ali Alsobiyl