One of the best articles I've read on EDH deck design is by a guy called Sheldon Menery. Yeah, he's the famous popularizer of the format, the Carl Sagan of Elder Dragon Highlander. All his articles are good, but this one takes the cake. Exploring the practical concerns of any deck, along with maintaining a theme to keep things interesting, Mr. Menery explores the body, spirit and soul of the EDH deck. Don't be a D-bag!