Talking about the quality expected and how it turned out.

The 5 success:

1) Zelda Skyward Sword

THE game of the Wii. Its motion controls is the definition of the console and the reason it exists. It has the best gameplay of all Zelda game, has great bosses and dungeons and just feels completely epic. The game is a fantastic success in itself, and even higher for proving that motion controls are the new standard. I don't want to play Zelda without now.

2) Super Mario Galaxy

One of the very best rated game of all time and for a good reason. Nintendo just set a whole new reference for 3D platforming. It surpasses by far all other game in the same genre, Mario 64 included.

3) Pokemon Black and White

Best Nintendo DS game. The gameplay is refined, the graphics are upgraded, the content is expanded, the story is much more interesting. Overall the game is a great evolution in the serie.

4) Donkey Kong Country Returns

A pure revival of the DKC serie, with hardcore 2D platforming at its best. I thought it was the best 2D platform game of the generation , even ahead of NSMBWii. And it was totally unexpected. The game was announced at E3, released less than 6 months after and it was a complete success.

5) Xenoblade

This kind of RPG is not my taste, and I have not bought the game. However, the consensus among gamers is that the game is stellar game, the best JRPG of the whole generation. When Nintendo bought Monolith, it did the mediocre Disaster Day of Crisis and while some people expected them to make a new Baten Kaitos, they released a game with close to no hype which immediately went into the references of the genre.

Honorable mentions : Mario Kart Wii, DS, NSMBWii, Elite Beat Agents

Mario Kart Wii should be number 1 on that list.

And now the 5 biggest disappointement:

1) Metroid Other M

When it was announced, it was huge. The whole gaming press was going crazy with the game, the involvment of Team Ninja had a lot of players excited. When the first videos came, the hype grew. When the first hands on were released, it was exceptionnally positive and the anticipation was at its highest. Finally, it turned out as a very big disappointement, it was slammed by a lot of reviewers, players were even more disappointed, Samus turned into an emotionally instable person, the game play was not that good. The game came from exceptionnal to mediocre. And it logically flopped hard.  THE error of the generation for Big N

2) Animal Crossing Wii

What was the point of even releasing the game? 0 interest in it if you had AC gamecube or DS. Lazy port. I seriously hope the 3DS will be better than that, the licence deserve much better. The Gamecube episode is now a classic.

3)  Donkey Kong Barrel Blast

Not hyped by Nintendo, not awaited by anyone, but it is still sad to see when Nintendo release a shovelware, and with such a strong licence.

4) Wii Music

Never turned out what it was supposed to be, felt weak compared to other music game and was quickly forgotten by everyone. The mess created of this game can still be viewed on internet. Lacked a lot of dept and had poor controls.

5) Golden Sun DS

Golden Sun was a serie on GBA which enjoyed a lot of success both commercial and critically and a lot of people waited for its return. At the end, it was good, but nothing special.

I respect SMG on the list.. is it the best In the genre? Sonic Generations may say otherwise

Sonic generations is a positive step for the franchise which seems back to good level but it does not compare at all to the best 3d platform game ever, SMG1&2

Metroid Other M is an excellent game. (Minus the crappy cut-scenes)
What's wrong with you?

Fair play if you reckon sonic generations is better but for me just no way. Generations is a much improved sonic installment whereas galaxy is one of the greatest games ever.

Odd list IMO.
Skyward Sword does show how good motion control can be I guess, which I suppose could be called a success.
Mario Galaxy is a success in that it is a dream to play through the first time.

In terms of Nintendo's successes of the generation though, I think the list should have been Brain Training, Nintendogs, Wii Sports, and then choose your pick for one of the Mario Karts and one of the New Super Mario Bros.
Actually it is hard not to add Wii Fit to that list... between them those 6 games have made an enormous impact on gaming this gen (I guess for impact it should be the DS versions of MK and NSMB)

Golden Sun DS was amazing. Really really amazing.

It's kinda funny really

What's considered a failure for Nintendo is often concidered a success for any other company