The Game Cube and XBox support progressive scan modes - 480, 720 and 1080. The PS2 does not, but that's the penalty for being the first out of the gate, I guess.
The problem is that not all games that support progressive scan modes also support widescreen TVs. So they get all stretched out. I refuse to play like that, so I have to eect the disc (on the XBox), go into the console's control panel, and disable progressive scan modes.
Some games look just effing fantastic at 480i widescreen - Project Gotham 2, Panzer Dragoon Orta, Freedom Fighters... Some PS2 games support widescreen and they look very nice, as well. GT3, for example, looks like an entirely new game on a wide HDTV, using component.