Originally Posted by Chris White
I should mention that I'm in the same boat. Between the 5DII and the 24-70L, my camera is already a beast to carry, so the extra half pound is totally worth it to "get a grip" on all that weight. I don't even have a spare battery yet, maybe if I start shooting more video or weddings, right now I can get 1200+ shots on one charge, so the grip is strictly for ergonomics.
I had a Rebel XT before the 5DII, so that thing was easy enough to handle w/o one, but I think that with any of the bigger, heavier cameras, the grip is a must.