Extra battery pack or a battery grip and which ones?

[nitrous642]

Hello all,

I've looking around how to extend my 600D's battery life and I was thinking either buying a battery grip or an extra battery pack.

At this point I am unsure which one I should go for but I came up for instance with the following while looking into Amazon,

Canon Battery Grip

Canon LP-E8 (which I think is an original Canon replacement battery pack for 600D)

Cheapest Canon fit battery grip + 2 x battery packs

In addition while browsing Amazon I've found lots of grips and battery packs other cheap more expensive and so on.

In your opinion which one should I go for?

Thank you very much!