Can you play them with the gamepad or do you need a wiimote?

I'd recommend:

- Mario 3D World

- Pikmin 3

- Rayman Legends

- Monster Hunter 3 Ultimate

- Sonic All Stars Racing Transformed

- Need for Speed Most Wanted U

- Wonderful 101

- ZombiU

A second screen is awesome!
U are watching netflix on the TV, and your mom come to see something, so you stantly change to gamepad witout even pausing! I love this feature!
Start, navigate, play the games without turning the TV on! I like it a lot!
It is better when the TV is not in your room.

The games everybody listed.
My list is pikmin 3, batman arkham city, zumbi U, mario 3d wolrd, WWHD and NSMBU/NSLU. looking forward for rayman legends, DKCTP, mario kart, ssb, X, CARS, Sonic lost world, watch dogs

Is a great experience, Im very happy!

I'd recommend getting a Wii U first since there's not much out there for PS4 yet, because you have access to more games, not only from the Wii U, but the Wii as well... Get the NSMBU Bundle since you already get two good games. If 2D Mario isn't you're thing, then get the Wind Waker bundle... If neither are your thing, you should probably not get a Wii U. You also have all the virtual console games to consider as well. I didn't own a Wii, so getting a Wii U was an easy choice for me. Other games I'd recommend are listed below

Recommended games.
Wii U
-Super Mario 3D World
-Wind Waker HD
-Pikmin 3

Wii
Twilight Princess
Super Mario Galaxy 1 and 2
Mario Kart Wii

As far as I know you still need the Wiimote to play Wii games even though the GamePad screen shows what you're playing. -_-

Don´t buy the Wonderfull 101!

The Best Wii U game by far is Mario 3D World, thats the one thing you have to pick up. Everything else is just optional.

Wow! You guys really want me to get that Wii U. Soon as I get out of my debt that I got into with some car repairs, I'm gonna look into getting one of these bad boys. I may even hold off on the PS4 for a while...depends on which I can find a better offer for. Lots of games on here that I would like to play on the WiiU.
And yes, I did not own a Wii and only played temporarily with one at one point.

Gamecube save data could never be saved on the system memory of the Wii (unless it's a modded Wii) Those saves will be safe and sound on the GC memory cards as long as you don't go into their own menu and format them.

If you never had a Wii, you sorely NEED to play the Galaxy games, and Metroid Prime Trilogy (especially if you didn't have a GC either) That's the ones I see as most important. I've spent AT LEAST 250 hours with each and every one of the games I mentioned, Galaxy 1, Galaxy 2, MP, MP2, and MP3. Not saying you should do the same :P But just saying they're really, really good games. Some of my all-time favorites.

For Wii U games, there isn't much that I've been very happy with, but I guess Mario 3D World is a fun party game. Also try Pikmin 3 if you want a more deeper single player experience. 3D World didn't do it for me, even if it's a masterfully designed game.

I haven't been near a new Mario game since the original NES days...it's just not a franchise in which I hold much stock. But it's high time I get on that horse too...also, I'll have kids at one point, I want to have friendlier franchises to share and play with them.