Xbox 360

1st Logo (Late 2004-November 3, 2010)
Visuals: The first element shown is the top of a large sphere against a white background in dim light. As the room begins to light up, the large, pointy green "X" lands on the right side of the sphere and shoots out a green ripple. The sphere then rapidly zooms out with a green aura and spins around clockwise so that the "X", which is deeply cut through the sphere, faces us. Another green ripple shoots out from the sphere, turning the background pale green and forming the words "XBOX 360" below, with "XBOX" in green, "360" in gray, and the middle line of the "B" extending slightly out to the left. The sphere shines, and a small black Microsoft logo fades in below seconds after if you have a game in the tray and auto play is turned on.

Variants: A variant was used before the Xbox 360's release date. The green background is different, the music is remixed (the synth chord pans across the stereo channels) and the Xbox 360 text moves slightly.

Technique: CGI. This logo was created by Imaginary Forces. It's animated at 30fps, but when the X is shown, it switches to 60fps.

Audio: A dreamy synth tune with a few whooshes as the sphere forms. It ends with a fading synth chord (from the XBOX 360 game commercials) when the words are formed below. It was composed by Audiobrain.

Availability: Seen when starting up the Xbox 360 before the November 2010 Kinect update (including the 2004 Development Kit), but it was seen in early builds of said firmware update.
 * It can be found on older systems that were manufactured before the update but not updated since November 2010, however the rarity of a Slim model with this startup is higher (only a period of five months existed between that model's introduction and the update).
 * The stakes are raised considering the original models were infamous for hardware failures and/or the Red Ring Of Death (caused by GPU chip failures from power cycles), so you’re lucky if you either find or own an original model that still works and was never updated.

Legacy: This was a memorable logo for Xbox 360 players of the time.

2nd Logo (November 4, 2010-November 12, 2019)
Visuals: On a white background, we see many lines in shades of green swirl and form a gray sphere. A thick green trail forms and flies around as the sphere zooms at us, then zooms to its natural position as the green trail flies into the middle of the sphere, forming the same green "X" as before. The words "XBOX 360" (in the same colors as the previous logo) zoom in as the "X" glows for a second. Like the previous logo, if there's a game in the tray and auto-play is turned on, the Microsoft logo appears below.

Variants: Starting with a software update released on June 10, 2013 (the same day as the E model's unveiling), the green colors (notably the Xbox text) are darker.

Technique: Again, CGI. It runs at 60fps.

Audio: The sequence begins with a synth note similar to the last logo. Then we hear a few whooshes, and a low-pitched version of the last note.

Audio Variant: On dashboards "2.0.12209.0" and "2.0.12275.0", We first hear what appears to be a group of kids laughing, followed by a remixed version of the 1st logo's synth note with whooshes, the whooshes are then stopped by the same low-pitched version of the last note.

Availability: While no longer current due to Microsoft stopping the production of the system in 2016, it can still be seen on Xbox 360 consoles after the November 2010 Kinect update (including most Slim and all E models). This was first seen at Microsoft's E3 event in 2010.
 * This logo can also be seen when playing an Xbox 360 game on an Xbox One or Xbox Series console.
 * The early audio was only on dashboard builds "2.0.12209.0" and "2.0.12275.0", and it briefly went back to the first startup in dashboard build "2.0.12293.0" until it was replaced by the final version of this logo the next build later.

Legacy: Like the previous logo, this was also a memorable logo for Xbox 360 players, both coming from the early years of the console and recent players.

Final Note
After ten years, Microsoft decided to stop the production of the Xbox 360.