Sparrow3
Prince
Intelligence Agency gives 8 EP and +50% EP, and is 180 hammers as I recall.
Security Bureau gives 8 EP and extra chance of catching spies in the city, and I think it's 220 hammers.
Build whichever one you need the benefit of more. Generally I find the Intelligence Agency more useful... plus it's cheaper in hammers. It usually comes later though (depending on your tech order), so you may not have a choice during some parts of the game.
I guess what I was asking is which is more effective: +50% EP or extra chance of catching rival Spies. I really hate having my water supply poisoned by my rivals. I have actually gone to war over it.
