It might be a safe presumption that if she likes Wii Sports, she'll like Wii Play also. Don't forget that Wii Play is bundled with an extra Wiimote (but not Nunchuck), so then the two of you can play together simultaneously.
We went looking for the Wii Play / Remote combo but had no luck so we just picked up a remote.
Being that we have people over alot and play games I figure we will end up with 4 remotes at some point and get Wii Play with the purchase of one of those.