Where do you teach? Conversation school? Mainstream school? International school? Your needs may be different depending on what type of institute you work in.
Longman is just one publisher of ELT books. Have a look at the many others out there (Oxford, Cambridge, Thomson, just to name a few). Ask for sample copies and thumb through them. You can't really get a good feeling for books just by looking at the blurbs in the catalogs.