I think all three have potential to be million plus sellers, hope that YNI isn't hindered by the team developing it.  I personally very much liked the DS version, but know I am in the minority.  I know that DK no longer holds the majorities appeal, but from what I've seen, it's a great game that I hope to play with my family  this holiday season.  Mario Kart always has appeal.  I look forward to it being awesome and selling likewise.  Probably even best overall, but I also look forward to SM3DW... yes, I don't own it... Yet.