At the E3 conference of 2001, Nintendo's GameCube first made its appearance, Microsoft's initial Xbox game line-up was unveiled, and Sega's Dreamcast made its last appearance.
Nintendo's games included titles like: Super Smash Bros Melee, Super Mario Sunshine, Pikmin, Eternal Darkness: Sanity's Requiem, and Luigi's Mansion.
Melee alone sparked the formation of competitive Smash Bros communities across the United States and Japan. The fighting game scene centered on Melee saw a history of technique developments like Wave Dashing, Dash Dancing, and the overall development of character play-styles. Player names like Mew2King, Mango, Leffen and Armada were (and are) widely known names in the Smash Bros community for their high level of play. To this day, Melee remains a highly competitive game that is featured in MLG events such as Anaheim.
Another major event of the 2001 conference was the Microsoft conference that featured the first installment of the critically acclaimed Halo franchise.
[via Halo Nation]
The FPS Halo: Combat Evolved, which gave rise to the machinima style series Red vs Blue, was innovative in the development for split-screen and multiplayer experiences, and went on to release incredibly popular sequels like Halo 2 and 3. Halo 2 would be the primary feature of MLG's Pro Series in 2006, which was the first televised video game console league.