I think VGChartz will be pretty close, but still off by 10% or so. Games that could certainly be off: Pokemon (could be a bit higher, upto 15%) Guitar Hero 2 X360 (higher, upto 10%) Super Paper Mario (again, higher by 10-20%) Wii Play could be slightly too high, but I could be wrong. Overall, should be pretty close.
Back from the dead, I'm afraid.