In the current top 40 all-time best-sellers, there are 9 games from last gen...
GTA x 3
GT x 2
Pokemon x 2
Halo 2
FFX
You could arguably count the Sims and WoW for being in the same time period, but I'm just talking console generations.
There are already 7 from this gen... All Nintendo games, from 6 different franchises!
Nintendogs
NSMB
Wii Sports
Pokemon
Brain Age/Training
AC: Wild World
Mario Kart DS
And it won't be too long before Wii Play, Brain Age 2 and Halo 3 reach the top 40.
"[Our former customers] are unable to find software which they WANT to play."
"The way to solve this problem lies in how to communicate what kind of games [they CAN play]."
Satoru Iwata, Nintendo President. Only slightly paraphrased.