Nikon D90 w/18-105 kit lens
the 18-105 is a great walkabout lens for the price. or you could look around for a combination of the 18-55 vr plus the 55-200vr, both are insanely cheap used. the 55-200vr is pin sharp too.
a more costly option is the 16-85vr with better optics than the 18-105.
also, the d7000 is going for a great price if you can stretch your finances. a slightly better camera but not as forgiving to the beginner as the d90.