Maybe not all time, but one amazing game that wasn't mentioned in this thread was Flash vs Calm on Fighting Spirit in the OSL round of 8 (or was it 4?) last year - Game 3 I believe. It was an epically long TvZ, tensions were high the whole time and neither player could really do any damage to the other for almost the whole game.
Of course there are epic classics. Of the more recent games my favorites are:
Much v Bisu on that semi-island map where Much does 1 base carrier. Quite a game that was.
Jaedong v Fantasy on Outsider. I think this was the game which really kicked off the SK -> Mass tanks TvZ style
Iris v Bisu game 5 of their MSL series. This is definitely my favorite TvP ever.... such insane opening transition to seriously (and well) used hallucinations? Yes please!
Flash v Movie on HBR. This is because I'm a Flash fan, you just have to admire his defensiveness.
Flash v FBH on.. well most of their games! Particularly Medusa and that T favored 3 player map last fall (Moon glaive?). What insane TvTs....
I know technically it may not be remembered often or had great skills displayed but Boxer VS Pusan set 3 on ROTV was what got me into Broodwar. EDIT: And awesome! Right above me people are talking about it. Fantastic game
Fantasy vs GGPlay on Neo Medusa -> the day the Fantasy build was unveiled to the world.
Nal_rA's Hallucination Recall game AND his epic elimination match against Savior.
The ENTIRE Boxer vs Anytime So1 Finals (If you had to pick a game, pick game 4 for epic minetraps). I thought this was just as epic, if not more epic, than the Boxer-Pusan series.
Jaedong's EE HAN TIMING muta-scourge attack vs. Stork in EVER OSL 2007 Finals
Heck, I'll even throw in Effort vs. Flash in Bigfile MSL for Effort selling Flash, who the commentators noted 눈치백단 (maphacker), the big 2-hatch lurker fake into ultrafast defilers.