I fail to see the reason for a Nook Color if you have an IPad. I would imagine you can read the kids color books on the IPad using the B&N app.
I guess the idea of a more portable 7 inch e-reader could be appealing but unless you are going to be out without the IPad regularly I can't see that as a good reason.
Or you could really like gadgets and want an Nook Color and you have the extra cash to spend. If so, go for it.