Pikachu is just as big, if not bigger than Mario, Sonic is non-relevant these days. This isn't even a question that should be asked.

I think it'd have to be Pikachu is only for the 15 and under demographic. (Well and the parents that buy their kids this stuff.)

Actually something I hadn't thought about before.  Not sure if that's a bigger knock against sonic, or just a compliment for Nintendo and their ability to seemingly create huge mascots anytime they want.

In another 10 years or so, i could argueably see Pikachu passing Mario.

Mario hasn't been in a TV series for 16 years. And 15+ movies. I pick Pikachu. He's been in the Thanksgiving parade float a million times, for god sakes.

Yeah, but Mario is the first character people think about when you hear gaming.  He's probably as noticable as Mickey Mouse.  Pikachu isn't as well know to older people.

I did this to prove you wrong..

http://www.google.com/trends/explore#q=pikachu%2C%20sonic&cmpt=q

Woops...

In pop culture, Sonic.
Pikachu is probably more popular among those growing up in the late 90's and early 00's.

Sonic the hedgehog - 24.3 million results

everyone who knows pokemon knows pikachu

pokemon 277m

batman 328m

superman 171m

sega 125m lol

Do you really think so? Literally everyone and their grandma knows about Pokemon, and the first Pokemon everyone will tell you he knows is Pikachu.

Pikachu is substantially bigger than all other video game characters, including Mario. But it isn't because of the video games at all. I mean, practically no one associates recent Pokemon games like Black and White with Pikachu.

It's just that the anime/movies of Pokemon are a pretty big deal right now and were an enormous deal up until a few years ago. Through the anime, Pikachu is probably very well-known to huge audiences that know nothing about gaming in places like developing countries.