Seeing as the magnataurs got nerfed and all I probably shouldn't be posting this until I'm done using it, but here goes:
In the green little area called Ruby Dragonshrine in Dragonblight (Northrend) there are several friendly dragonkin called Ruby Guardians fighting Frigid Ghouls.
Now what does that have to do with me, you ask.
The thing is, those little buggers have a 3-4 second respawn timer and rewards xp as a normal lvl 72 mob. They're easy and safe grind if you're there, and perfect for a very simple bot.
All you need to do is place any kind of ranged class near the guardian and spam one or 2 spells, with an autoit bot, or a G15 keyboard. The dragon will kill it and you'll get almost full xp.
Simple, safe, and noone really notices you standing there.
Sidenote: They also drop loot.
Another sidenote: The next mob spawns close to the place the last one was killed, so if the Guardian is fighting too far away from you, just kite the Ghoul near you and kill it there...