The short answer is that because of the leveling buff it's probably better to just flat out quest in areas from 20-60. I would recommend using a guide for the best questing paths and routes though.
I too have used Jame's leveling guide for nearly all of my characters. The site for it is
World of Warcraft Pro | Brings Game Experience to You!. It's very comprehensive and following it to the letter made for fast leveling before the leveling was made easier recently. It's also free!
I leveled a Troll Shaman from 48-58 pretty quickly following that guide, and thanks to the leveling buff and quest experience increase, every level for those ten levels took barely over two hours. The best part was I was constantly two levels ahead of where the guide had me, and as a result it made every quest that much easier.
For me personally, I just looked up what the best spec was for my class and bought the best Blue weapons for level 40, and then again for the 50's, I did not find it necessary to do any enchants save for my gloves having +15 strength. I was able to blender stuff pretty quick though thanks to Windfury.
I think it just comes out to the best leveling spec for your class which is either going to be based on super damage output or super survivability (like AoE grinding as a Protection Paladin from level 50 up).