attached is a review of the 2 lenses which might help provide more information...9mm said:Question: Can anyone comment how the Nikon's kit lens is "better" than the Canon's one? In terms of reach? OR?...
http://www.digitalreview.ca/cams/NikonD70vsRebelXT_pg2.shtml
kit lenses tend not to be of very high quality, but provides a new user with a lense with sufficient range and flexibility to start out with their new DSLR. having said that, i personally think that the nikon kit (18-70) is a better far lense compared to the canon kit (18-55) in terms of range, sharpness, colour and contrast.
having said that (again), if you are really going for quality shots, chances are, you would eventually "upgrade" from either one of these kit lenses.