Half Life 2. It was neat when everything slowed down - explosion and all - then froze. I said 'Woah'.
Like Neo.
So, yeah - either HL2 or Eternal Darkness.
AND!
While we're on the subject of game endings. At the end of Starfox Adventures: Dinosaur Planet, the final building you go into - the big one - I can't be any more specific - is the floor texture in there, the same as in the Carrington Institute bottom-level lobby on Perfect Dark? I'd check, just to make sure, but I sold Dinosaur Planet when I finished it. But I think it is the same, from memory.