The .cue you'll need for games that have audio tracks, such as Alien Trilogy, Dead or Alive, (those are off the top of my head) If you play those games I mentioned, or any game with audio tracks, without the .cue, you'll get this nasty distortion sound.
And if for some reason, your .bin does not have a .cue, there's this great app called "MakeCue". And if your game is either .bin .iso .img, just create the .cue, when it's completed, open it with either notepad or wordpad, and edit the title to whatever type it is, EX - "whatevergame.bin" or "whatevergame.iso" or "whatevergame.img". I say this because, when you use MakeCue, it automaticly creates the name of the game as a .bin file. Hope this helps!!