I ran weekly pet farming circuits on several toons.
AQ40 > SSC/Kara/TK > Naxx = profit but the pets from BWL and MC sell for peanuts. Prices ranged from 500g to 5000g per pet and became my largest source of gold. Battle pets, people can't get enough of them!
Farming Pit of Saron for the Hilt isn't a bad way either but it's even more RNG dependent and you'll hit the max instances/hour but you also come out of it with tons of crafting materials.