Light Fingers-

A must for any fan of lightening everyone else’s load (by taking the burden onto oneself, naturally), Light Fingers is less effective the heavier and more expensive the item is, but with a maximum of doubling your skill value, there’s no reason not to maximise this if you use the skill with any regularity.

Night Thief-

This perk stacks with Light Fingers, improving your chances even further- but only if your target is asleep.  That means engaging in some breaking and entering- so you likely only have an interest in this specific perk if you also have a few of those nice lockpicking and stealth perks as well.  Still, put together with Light Fingers, it becomes easy to take someone for everything they’ve got.

Cutpurse-

As though Light Fingers and Night Thief weren’t good enough, Cutpurse makes any attempt to steal gold a virtually guaranteed success.  As gold is among the easiest things to steal to begin with, the perk is virtually unnecessary- but there it is, all the same.

Poisoned-

A key method for not only completing Dark Brotherhood assassinations but just generally getting rid of people you don’t like or want the chance to loot, Poisoned lets you reverse-pickpocket someone’s blood.  Since the poison takes effect directly as though it had been stabbed into your mark, you can use it to immediately kill many civilian NPCs, and if you’re anticipating a fight with someone you’re about to talk to or act overtly near, this can make a huge difference in the upcoming battle, draining resources or even just leaving your eventual target with very little health for you to shiv out of them.  Or, if you just like being a jerk, use it to give someone Paralysis.