Photo's look fine to me.. I suspect you were expecting too much (they are only kit lenses after all)
Agree with others about your white balance being weird.. (not sure why its looks so bad - normally auto isn't that bad)
Also you might find photo's to be a little sharper when you are shooting in the lens's sweet spot
Shooting wide open (F3.5 at 18mm or f5.6 at 55mm) or very closed (f22 etc) wont yield the best results
(ie all your book shots for example are at 5.6, dog is at f11 and looks perfect, and car one might just have the focus off a little)