Just stuff from my Beta Files. During Beta found this spot at Malykriss: The Vile area in Icecrown to be the best grind spot of any the last two zones for lvl 77-80 grind if you like to grind stuff. I remember a quest sends you there to check something in the area. Area not named on the zone map but its just north of Icecrown Citadel where the huge chunk of metal suspends in the air with chains overhead and gargoyle's guard the area along with Aboms at the entrance. But its all undead mobs that respawn very fast. From Beta remember the mobs spawn there in less than 30 sec and real nice to grind for fun or XP. They are other areas in Icecrown but this I remember was the absolute best for easy XP.
Related: WotLK Beta. Somewhere in Northrend
A wired grind spot in Storm Peaks just east of and outside of Brunnhildar Village where the lvl 80 Brunnhildar mobs path attacking the frost giants. If you just happen to be standing in the right area you will be in the middle of all their paths and end up you can just park and pile up mobs non stop for XP with barely time to loot. Don't think its really a grind spot, but the mobs runs that path back and forth and just happen to find it by accident in Beta as such just standing around mounted in the area.
lots of various Elemental mobs or Spirits on the Western edge of Sholazar Basin or "The Stormwright's" I think its called.
Sholazar Basin. The very Western edge of the zone is only accessible by flying mount and all the various mobs there are Elemental/Spirit mobs which yields various Crystallized elements of Crystallized Air, Water and can't remember what else mobs spawn there on the shelf. But the shelf runs the entire length edge of the zones with mobs.
Some Crystallized Fire you can find in Borean Tundra from the Fire elemental mobs there also in the northern part of the zone. Grizzly Hills zone have some Elemental Spirits in the eastern part of the zone where the rune mobs are that also drop Crystallized Air I remember also. There are several caves in The Storm Peaks zone that have various Spirit mobs that drop Crystallized elements of various sorts also if you like to explore. If you mine allot you can get the rest of many the other Crystallized Elements to make Eternal Air, Water or whatever else. Just stuff I remembered in Beta from all the many screenshots.
Edit: Western Edge not Eastern Sholzar Basin.