Leveling

48-53
In the very North West cornor of Feralas there are harpys. Ranging from 48 to 53.
Harpys
http://thottbot.com/?n=394718 (lvl 48's)
http://thottbot.com/?n=12363 (lvl 49's)
Grind these harpy's from 48-53.
I found out that having healing potions and useing a Elixer of the Mongoose (http://thottbot.com/?i=14407) helps a lot. For melee class's.
There is a good chance of being ganked by lvl 60's cause at that level your easy prey.
You should be able to grind a least 40k exp a hour and get descently good greens and runecloth if i remember correctly. I am a warrior so it might be a bit different for each class.

53-57
In Azshara there are Blood Elves and Legashi Deamons. There are on the upper part in the middle on the side towards the ocean.
Blood Elves
http://thottbot.com/?n=15145 (lvl 52's)
http://thottbot.com/?n=15170 (lvl 51's)
http://thottbot.com/?n=15145 (lvl 52's castors)
http://thottbot.com/?n=210858 (lvl 53's castors)
You can grind these mobs fairly fast, descent runecloth drops, and a few blues here and there. Only thing youll run into there is chinese gamers.
Legashi Deamons
http://thottbot.com/?n=154306 (lvl 52's castors)
http://thottbot.com/?n=23799 (lvl 53's castors)
http://thottbot.com/?n=22295 (lvl 51's)
http://thottbot.com/?n=224554 (lvl 52's)
http://thottbot.com/?n=24224 (lvl 53's)
These mobs arnt so bad, but the castors can be a pain sometimes. They have a chance to drop Felcloth wich is really nice, They drop cards too. Cha ching??? Well you can grind these along with the blood elvs. I killed so many so fast id go from blood elvs to legashi deamons and back and forth. It was really good xp. Probly 21+g per hour or so.

57-60
This is where Deadwind pass actually plays its part sometime in the game. Grind the ogres in the southeast side.
http://thottbot.com/?n=378534 (lvl 55's)
http://thottbot.com/?n=412393 (lvl 56's)
http://thottbot.com/?n=412393 (lvl 56's)
http://thottbot.com/?n=198350 (lvl 57's)
http://thottbot.com/?n=412396 (lvl 55's castors)
http://thottbot.com/?n=304790 (lvl 56's castors)
http://thottbot.com/?n=412394 (lvl 57's castors)
http://thottbot.com/?n=197005 (lvl 57's castors)
http://thottbot.com/?n=28503 (lvl 58's castors)
There are a ton of these mobs, and RARELY you find alliance/horde. They have some descent hp but theres so many they make up for it. They have runecloth and money drops. They drop blues and while i was lvl 58 i found a epic axe brain hacker. http://thottbot.com/?i=14001There are caves here wich you can go in and fight them too. They are easy if you have armor or are melee in general. Im not sure how the castors will work out.