Metroid is usually included for the reason that it was one of the first-party series that got immediate attention with the release of the Game Boy and Super Nintendo, alongside Mario and Zelda. Yes, it goes back that far. Even when the N64 shifted the whole paradigm by having no Metroid and Zelda late, long-time Nintendo fans still considered Metroid to be one of the important Nintendo franchises. The GameCube having a Mario, Zelda, and Metroid all released near one another, combined with the Wii's getting a Zelda, Mario, and Metroid all within the first 2 years of the system's release, seemed to bring back the Game Boy and SNES days in that sense.
Although really, Nintendo's biggest three franchises now are the Mario, Wii, and Pokemon series. Zelda is a comparative lightweight to those, and Metroid hardly even registers as a blip on the sales radar by comparison.
Sky Render - Sanity is for the weak.
