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.
I still play PS1 games, too. I just bought Um Jammer Lammy a few weeks ago, and I've been looking for the original PaRappa the Rapper to go with it. I also give FF7 and Metal Gear Solid a run through every so often, although MGS will be obsolete soon.