sent back the a200 Sony the SSD was all kinds of messed up. For my wife who does not mind reading manuals and learning ...replacing our 5 year old point and shoot.

she wants a SLR

I am not familiar with Nikon, but Canon xs is very user friendly and has a nice grip for a woman's hand

is it a big jump $wise to the d90? if not i would highly suggest going for that
it really does have a much better feel, than those 2, better AF and AF points
the nikon is more user friendly, but image quality wise there is no real difference