I've bought the following "hardcore" 3rd party Wii retail games this year (all at full price, and most M-rated): Madworld, House of the Dead: Overkill, The Conduit, A Boy & His Blob, and Silent Hill: Shattered Memories. Aside from A Boy & His Blob and Silent Hill, I regret buying all of them and I only still own Silent Hill.
Sales sucked on most of those titles for good reason. Those latter two titles I listed were the only two who deserved to sell big.