There are many leveling guides out there. All of them will have you leveling faster than you ever have. But is one of them the fastest leveling guide?
Truth be told, most of them are really good. Zygor, Joanna, Dugi's, Brian Kopp, IDemise... they do the job well. Leveling from 1-80 has never been easier than it is now.
The real question is, "how do I choose between them?" You need to look at what the guides come with to get the answer.
All of the above guides come with an in game add on that will show you exactly what to do, and when. Most of them come with a talent guide to have you maximizing your DPS and survivability. They all have you leveling 100% by questing. But from here, there are differences.
You want a guide that comes with a support forum. If your add on has a glitch, or you have questions on the questing path, you need to know you have a place to turn to.
You need to have the guide include class quests. These are some of the most important quests in the game. Can you imagine leveling a shaman without totems? How about a warrior without defensive stance? You need to be doing your class quests, and the fastest leveling guide will make sure they are included.
Having a gear guide greatly helps too. Some players will go through the trouble of having the best gear at all levels, but many of us are content with having the gear that will have us leveling quickly without breaking the bank.