Unless you really can't afford the WiiU don't by a regular Wii. The system is 10 years old, isn't very well supported anymore and virtually no new games are made for it. Wait for Black Friday and I bet you can get a decent deal on a WiiU.
And see, I would tell you to get a refurbed one from Gamestop so you can to even see if it's something your family will use. My DD is not and never has been a gamer either, but we thought she and her friends would like all the dance and sports games so we bought a Wii as a family gift 3 or 4 years ago. I bet it hasn't been turned on 50 times. Just wasn't a good investment for our family at all. Tough decision you have there.