I NEED ONE

Umm take all the sneaky related trees?

lockpicking
pickpocket
stealth
any of the combat trees will do depending on what you envision your thief doing to defend himself
Magic.... up to you really I might go with illusion if I was going to take anything.

Seriously try using that lump of grey matter between your ears first before asking someone else to design your character for you, this isn't an MMO you don't need to be optimal just play how you want.