MMMK well this is ENTIRELY dependant on your spec and gear...but here's 2
Location: Felwood, Irontree woods
Good:
Drops essence of water at obscene rates, only 3-4k health and they go down fast.
Not Good:
Sometimes camped, but can be avoided completely by doing this at night.
Poison you, but not for alot and only 100 damage every 10 seconds or so.
Location North western Silithus.
Good: there's around half-casters there that can be taken out easily ( only 3k health and can be counterspelled.)
Not much competition
Decent drop rate of text
5-10 silver a mob
Runelcoth
Cenarion Circle rep
Drops green cloth pieces that sell for 30-60s alot.
Not Good: Gear isn't a must, but it helps. My gear is pretty decent ( ZG dagger t2 helm a couple of rares from ZG, and I have no trouble ) If you're decked out in greens though you may want to try something else.
Location: South Winterspring, Darkwhisper Gorge
Good: very very very little competition if any ( I have never found anyone else here ever)
Chance to drop a boe epic priest item which goes for 300 gold easily
http://www.thottbot.com/?i=37476
Drops lots of silver, and easy to kite
Not Good: You MUST be frost. All the above suggestions are fire just an fyi.
Location Azshara, Bloodelf Encampment.
Good: VERY VERY VERY low health. as a fire mage I usually 2 shot these ( they have 2.2 k health )
They drop 3-7 silver
They drop runecloth
Misc greys that can sell for a decent ammount
Not good: not enough room for more then 2 people and they are sometimes camped.
Location: Azshara, Haldaar encampment.
Good:
They drop felcloth which is around 2g each at 3%
Multiple camps ( 3 )
3-7 silver
Decent Runecloth
Drops vendor junk (1 gold or so )
Chests spawn at camps also.
Not Good: Well, they pretty much are only good. Only slight drawback is 2.5k-3k health which isn't that bad really for what they drop.
Use the AH for your advantage ( not what you think necessarily), I have a guide in the submissions forum that deals with that in alot of detail, and I don't want to let the non-member's see it I guess since it may not be counted then.
Location: North East silithus, rock elementals.
Good: great for grinding as a frost mage ( if that's what you are )
Drops tons of vendor junk which adds up quick.
Solid stone
Essence of earth
and MC rep.
Not Good: Must be frost and they have 4k health
Location: SE of everlook.
Good:
They drop winterfall fire elixir which can sell for a decent ammont
They drop 3-7 silver
They drop Runecloth
They give timbermaw rep.
They are used for a quest with the winterfall saber trainers( not sure about the faction name, but if you get exalted you can ride an uber tiger mount =D)
Drops Misc grey loot
Near town
Not so Good:
If you're doing the rep quest you have to run back after 10 kills
Well, there you go. My complete guide =D.
I'd appreciate greatly any TU-bucks you could toss my way.