2000. The roster was crazy stacked that year with Rock, HHH, Foley, Undertaker, Kane, and Austin later in the year at the top of the card, an amazing Mid card with Angle, Jericho, Benoit, Guerrero, Rikishi, etc. and an amazing tag team division; Hardyz, Dudleys, E&C, Too Cool, APA, and so on.
On top of that you had the perfect combination of unpredictable attitude era storylines with amazing wrestling to compliment it. That entire run from Royal Rumble 2000 - Wrestlemania 17 is wrestling perfection.