Which are the best games you've ever played, and why?

[Final-Fan]

Chrono Trigger - This has amazing storytelling, great (and early) use of multiple endings, and probably embodies the pinnacle of pure RPG gameplay -- sadly, no one has built on its combat engine.

Final Fantasy VI - This is the best in the FF series: many strong characters, great story, and the best villain.

Final Fantasy Tactics - If there's a better tactical RPG, I haven't played it.

Super Mario 64 - I shouldn't have to explain this one. This game is still in many ways the gold standard of 3D platformers. It was rereleased eight years later (DS) and was a smash hit, despite criticism that the original had better controls.

All the Mario Games - All of them are masterworks.

The Legend of Zelda: Ocarina of Time - I will not explain this one.

All the Zelda games - Every bit as good as Mario.

Resident Evil 4 - This game was ported to a system three years and one console generation later. I bought it and played all the way through on all 3 systems it was released on. Need I say more?

StarCraft - This ate my life for about two years. I plan to feed StarCraft II at least one more.

Diablo II - This ate my life for about two years.

Einhander and Ikaruga - two greatly innovative (and just plain great) SHMUPS, with Ikaruga having the advantage of being AFAIK the swan song of the genre.

[edit: Mega Man 2 & 3 collectively - the pinnacle of Mega Man. The fact that Capcom is still making Mega Man games is a testament to how good these two games are.]

(Final Count:
(11 games, 2 series
(4 games by Square
(2 games, 2 series by Nintendo
(5 games on Nintendo consoles (& two ports)
(5 sequels - not counting FFT or Ikaruga)

[edit2: I have not played Half-Life or Half-Life 2, but from what I understand, if I do, I may be wanting to amend this list.]