As another guy looking to buy a DSLR for his wife, I recommend looking at either a Nikon D5300 or a Canon SL1.
I have borrowed my sister's Nikon D7000 and we have friends with Canon T3i, 40D, 50D, and 60D that we have looked at. She (we) thought that we wanted either a D7300 or a 70D. Then she saw how heavy they are and said that she wants something lighter. She didn't like the idea of carrying a heavy camera and lenses (even though we all know I would be the one that gets saddled with the pack)
We have been looking for a while and not settled on one yet. The D5300 and the SL1 have most of the same features as the other DSLR cameras mentioned here, but they are also the lightest. They are cheaper than the others, too. I suspect that both price and weight are benefits of the lighter, plastic body instead of the metal bodies of the larger models.
Before you buy one, go into a camera store and actually use the menus on the cameras. Play around with the ISO, aperture, shutter speed, and white balance. Which ever camera feels better in her hands AND is easier for her to navigate the menus......that's the one I recommend!
Good Luck!