The Xbox 360 started off as Project Xenon over at Microsoft slightly after Xbox Live came out on the first Xbox. It represented a completely new start with new hardware partners. Rather than sticking with Intel x86 chips that they used in the Xbox Microsoft opted for a triple-core PowerPC-based CPU from IBM dubbed "Xenon". Not content to stick with Nvidia chips they hired ATI to develop a very powerful graphics chip called "Xenos". The console has 512 megs of 700 megahertz GDDR3 RAM and has a 21 GB/s front side bus, a built-in 100BASE ethernet port, three USB ports and high speed wireless controllers that can support two way voice chat. There is an detachable 20-gig hard drive technically optional.
The Xbox 360 started the era of high definition gaming on HDTVs or VGA monitors. There were some Xbox one games that had higher resolutions on a HDTV and the Dreamcast had a decent VGA cable but this is the first time all the games on a video game system are pushed beyond the NTSC 640x480 and PAL TV systems that have been limiting graphics on video game systems since the days of Pong and the Atari 2600. The old standard TV resolutions were long dismissed on PC games. No serious PC game would run a first person shooter at 640x480 on a large monitor so it is just about time that console video games moved beyond using the same damn limiting RCA video cables or a RF tuner.
The graphics of the Xbox 360 are so gorgeous that you can't actually express it easily in words. I can tell you that it can easily pull off full screen anti-aliasing, has a hell of a lot of ram for super detailed textures, enough power to run some really awesome physics, object specific motion blurring, reflections, but that does not tell you the amount of depth and detail that game developers can pull off with this hardware. This system is not just about doing the exact same games but with better graphics but it can enable games that were not technologically possible using previous hardware platforms. Games like Dead Rising the player has to run trough a incredibly detailed shopping mall filled with tens of thousands of zombies in massive detailed crowds that react as intelligently to the players stimuli to the extent that the living dead zombies can.