Wonderful online Bible study site that has concordances, lexicons, dictionaries, commentaries, and more.
Another useful site with passage lookup, keyword search, topical index, and over 20 versions of the Bible in English.
Christian Classics Ethereal Library
Hundreds of downloadable classic Christian standards, transcribed sermons, and commentaries by leaders of the Faith from the likes of E.M. Bounds, Andrew Murray, Teresa of Avila, Finney & Chesterton.
David Pawson Personal Website
Packed full of great teachings and resources.
David Pawson Teachings Archive
Mike Bickle Teaching Archive
Hundreds of hours worth of great teaching on a wide variety of subjects.