I'm gonna copy-and-paste segments of an article I wrote a while back about Wii's library. Here are a handful of games that I think make the console worth checking out...
Monster Hunter Tri, Tatsunoko vs. Capcom: Ultimate All Stars, Zack and Wiki: Quest for Barbaro’s Treasure, The House of the Dead 2 & 3 Return, House of the Dead: Overkill, Sonic & Sega All Star Racing, Madworld, Virtua Tennis 2009, Samba de Amigo, Sega Superstars Tennis, Sega Bass Fishing, NiGHTS: Journey of Dreams, and Sonic & the Secret Rings, Sonic Colors, Sonic Generations, Blast Works,A Boy and His Blob, Muramasa: The Demon Blade, Red Steel 2, Klonoa, Little King’s Story, Bully: Scholarship Edition, Metal Slug Anthology, Shiren the Wanderer, Silent Hill: Shattered Memories, Deadly Premonition, Okami, Pinball Hall of Fame: The Williams Collection, No More Heroes 1 & 2, Cave Story, Star Soldier R, Excite Bike: World Rally, World of Goo, Adventure Island: The Beginning, Alien Crush Returns, Bit.Trip.Beat/Core/Runner/Void, Blaster Master Overdrive, Castlevania The Adventure/Contra/Gradius ReBirth, Lost Winds, Mega Man 9 & 10, Military Madness: Nectaris, Phoenix Wright, Strong Bad, Swords & Soldiers, Tales of Monkey Island, Super Mario Galaxy 1&2, Metroid Prime 3, Metroid: Other M, New Super Mario Bros., Zelda: Twilight Princess, Zelda: Skyward Sword, Sin & Punishment: Star Successor, Fire Emblem: Radiant Dawn, Battalion Wars 2, Wario Land: Shake It, Excite Truck and Excitebots: Trick Racing, Mario Kart Wii, Punch Out!!, Super Paper Mario, Kirby's Epic Yarn, Kirby: Return to Dreamland.