What is Good Preaching?

Following from the comment on the post below, anyone like to volunteer constructive comments on what makes preaching "good preaching"? Or bad preaching. Lets include Bible application studies as well. What are the necessary ingredients (humanly speaking - let's assume the sovereign work of God by the Holy Spirit). Is relevance necessary? And, if so, relevance to what?

Some twitter-style short 140 character definitions would make for interesting reading