Figured I'd add to this: The Tea stall in Eastern Varrock gives better EXP than Men/Women and Farmers.
Here are 7 reasons why this is nice:
1. It has no fail rate because no guards can reach it, and the tea seller doesn't yell for help. (Even if he did Guards still can't reach him).
2. You can start it at level 5 thieving and go pretty far before it gets boring.
3. Banking is optional, you can sell the tea back to the tea seller immediately(For 0 Gold)
4. Tea is AWESOME!
5. You can spam click and get 2 cups at once, as well as the EXP that comes with it.
6. 32 Exp a cup, and up to 64 exp per restock of the stall,
7. 3-5 second respawn timer,
Overall you can potentially make 45k EXP/H with no fail rate.