When it's all said and done, it's likely to be Mario and Sonic as others have said. It's sold well in all regions, especially NA and EU, and is showing long legs.
IF, and that's still a big if, Kingdom Hearts 3 were to go to the Wii, it might have an outside shot, but doubtful. The games on the PS2 and GBA sold really well, but it looks like Mario and Sonic may put most games' sales to shame this gen.
Monster Hunter would have to really catch on in NA and EU to have a shot. Still, MH on a console doesn't sale like MH on a portable. I'd like to see that change, but it's doubtful.
The Conduit and Madden won't do it. It's rare for an unproven franchise to sell as large as Mario and Sonic is doing, which is what makes Nintendogs and Halo's big sales so impressive. The Conduit may do well, but not millions upon millions. It may not even be released in Japan, and won't sell much there if it is. If Madden were going to be that huge, we'd be seeing stronger sales on the Wii versions now. They are doing well, certainly the best selling Maddens on a Nintendo console for some time, but not going to take the crown.