I'm not really sure what would happen if you have IS in both the body and lens at the same time but I would really like it in body because I only shoot primes and none of them has IS. I would love it if the lenses has IS but i don't think Canon will do that any time soon.
So IBIS is my best hope.
Canon and Panasonic combine in-lens and IBIS to give another 1-1.5 stops of stabilisation to an already insanely good functionality (but Panasonic only have in-lens IS on primes longer than about 25mm. Olympus only have in-lens on their telephotos).