I think we all know Skyward Sword, for me, would go at #1 for the best game on the Wii, but as for Twilight Princess, it wouldn't crack my Top 10, and probably not even Top 20. It's possible it would be in my Top 25, but I don't know for sure. Either way, though, they're both great games.
By the way, here's my Top 5 Best Wii Games list.
5.) Super Smash Bros. Brawl
4.) Donkey Kong Country Returns
3.) Metroid Prime Trilogy
2.) Super Mario Galaxy 2
1.) Skyward Sword