Santa was kind enough to bring my daughter Karaoke Revolution, and we've been having a ball with it. But, the microphone looks like it belongs to a 70's cassette recorder. (It's the same style as the Mario Party mics, just black.)
I saw that Konami made a pretty nice looking mic for the PS2, but after Googling the crap out of it I couldn't come up with anything else for the Gamecube.
Rented MKDA and like it fairly well. The Konquest part of the game is about as fun as any tutorial can be. Sonya (with her new hair and "augmentation"... think DX Tori) and Cage are CHEEEEEEEEAP. The Krypt is SO LAME.