Well, that's IGN's choice based on their own review scores. The only thing we can do is to agree or disagree with their choice. I have to say all 3 consoles had a better year than last year, or at least an equal year.
The Wii surely had some big games this year. They had some big core titles, titles that appeal to the core and the casual crowd (Mario Galaxy 2 for example) and pure casual titles (like Wii Party). I don't know if it was the Wii's best year ever, but from my point of view it was at least better than 2008 and 2009.
The 360 had lots of exclusives, or at least console exclusives this year. It was definitely better than 2009, but it didn't have much for my personal taste. Mass Effect 2 was one of my favourite games this year though.
Now the PS3. In my opinion 2010 was equal to 2009, if not even a bit better. It had more than enough exclusives this year and I wasn't dissappointed with any of those I had bought. Sony showed again that they are able to deliver big quality titles, and even 3rd party developers delivered some great exclusives this year (like Yakuza 3 and 3DDGH). So, does Sony have the quality this year? Hell yes!
In the end it's subjective which console had the best exclusives this year, everyone should decide for himself.
I bought 2 Wii exclusives this year, 2 X360 exclusives, 6 PS3 exclusives and tons of multiplatform games. And based on my own experience the PS3 had the best exclusives this year. But this is, as I said before, subjective.