I have to disagree with those who say that
Eternal Darkness looks too much like it's original N64 design. While the character models still have some sharp edges in both the actual game and FMV sequences, if you compare screen shots from the N64 builds to the final GameCube version - the differences are very noticeable. Although the N64 was a great a system (and I would have loved it if ED had been released back then), there is way too much detail in the GameCube version that couldn't have been possible on the N64. I don't mind the fact the characters still look a little "pointy", Silicon Knights' impeccable attention to detail and gameplay is what made me choose
Eternal Darkness as the Cube's most polished game. Just look at the design of every background - it is probably the most elaborate to ever be used in any game - every single object is highly detailed.
The game never experiences any sort of frame rate slow-down. The control is solid. The crash detection is just about as perfect as it can get in a game (sure there are some minor flaws, but I have yet to see a game in this or the previous generation that didn't suffer from crash detection problems in one way or another) and the storyline is one of the most entertaining...EVER.
It is a combination of everything I have mentioned that makes ED the most polished game to me.
You have to remember that gameplay and story have to factor into the mix along with the graphics and audio.

With that said, I'm glad that Silicon Knights moved the game from the N64 to the GameCube. I also hope that they delay
Too Human so it can be a launch title for the successor of the Cube. I am sure that however amazing the game might be now - it will be even more of experience on the future console.