I have had a problem with the terms expository, textual, topical. Every expository sermon has a topic and should use supporting texts; every textual sermon should have great exposition and a topic; every topical sermon should have supporting texts and great exposition. I have heard men think they were expository but only gave a running commentary to a passage. I think of Paul's recorded sermons and they weren't very expository by our standards. I have preached verse by verse at times, and series based on themes, but always careful to give good exposition and supporting Scriptures.