The battery life I've seen in practice is significantly better than the published info (2x to 3x at least), and that's without any battery saving changes to the settings like disabling image review.
IM observing the same thing with my SL1. Life of the OEM battery that came with the camera is quite good for regular shooting. I've shot with mine all day and the battery goes down to about half. That's just stills, no movies or Live View.
As for batteries, I personally use only original Canon batteries in all my cameras. Others, however, have had good luck with third-party brands such as Sterlingtek or what Wasabi. The choice is really up to you. But do be on the lookout for counterfeit batteries. This is where you can really mess up your camera.
Wow. Thanks guys! I was noticing the same thing.. The battery life is fairly good! But I like to have an extra battery especially for videos and trips. I'm leaning towards buying the original. True that it's expensive but I won't run any risks. thank you all for your advice!!