I'm not a fan of these big superzooms. The image quality is mediocre at best and I think you'll be much better off getting a body and, say, a Tamron 17-50 mm f/2.8. You'll cover most situations with these focal lengths, it's comparatively fast and already capable to isolate your subjects, and if you get the non-VC version, it's actually a very cheap lens. Plus, it's agnostic, you can get a Nikon or a Canon.
In practical terms, I don't think you'll notice any differences. The fact that the Nikkor is slightly faster is not something that tips the scale in its favor. In any case, you can get better/faster lenses for both systems later. E. g. Sigma's new 35 mm lens is supposedly stellar and on par with Nikon and Canon pro glass.
Huh??
ithink that guy ment the sensor in the canon t4i is out of date, ive remember reading it uses the same sensor as the t2i i think?
and thanks for the tips. i guess one of the things i liked about the t4i kit lens was it has a silent motor focusing system which is nice but i didnt know these super zooms effect quality. it seemed a nice "all around lens"
ive never tried sigma or tamrom, are they as good as nikon and canons brand from your expereince?