Has everyone forgotten about Mario and Sonic at the Olympic Games? Did you forget about the success of Wii Sports? It outsold Zelda 3 to 1 in Japan. As long as they're smart and include a fair number of games with the same or more depth as the Wii Sports games then the sales of this game are going to be HUGE. The name recognition of Mario and Sonic and the fact that it will have online play(according to IGN) is going to be a huge factor as well. Miyamoto is involved with this game and odds are that the team behind it is going to include every single game that he tells them too. Miyamoto is a genius so this will definitely be a good thing. If this game is good, everyone is going to buy it: young children, teenagers, adults, elderly, males, females, etc. I wouldn't be surprised if this sells better than every big game coming out this year.
A few non-related things.
Heavenly Sword is by the makers of Kung Fu Chaos, wow. There is no reason to expect that it will be good.
Also, System Shock flopped because of Doom, System Shock 2 flopped because of Half-life, Bioshock will flop on the 360 because of Halo 3. It may sell better on the PC where there is less competition and a more loyal following, but it won't sell squat on the 360.
