I'll start.

Oh man. Metroid Prime. Wasn't that,
so awesome? Yes, it was, and if you disagree, you're
super wrong. The amazing atmosphere, the incredible level design, the super-cool effects, the great controls, the hard, but never unfair bosses, the whole scanning-mechanic and it's ingenious way to tell a story without ever breaking the flow of the game, the attention to detail, the visor effects... The music?

This game was so great. Now, everyone, post that you agree! And what you like about that game, and what we can learn from it.
To get you in the mood, have a
trailer. I remember this particular trailer being on a disc for a different game (which one? I don't know. Luigi's mansion, perhaps?)... I think I've watched this more often than this weird trailer actually deserved.
Also, Samus "death-scream" at the end?
That game had a
stylish way of telling you "you're dead". Lesson learnt: Stopping music can be super effective.
Tomorrow: A different game to gush about (the idea of this thread is to keep the discussion to one game at a time... but you know. whatever.).
I may or may not ignore suggestions I get via PM.
Let's see how this thread will go. If it continues, you may bet on how long it takes until I finally post about Pokemon