You are misinformed when you say that the things the 20 gig model lacks can be added... you can't add HDMI, wi-fi, or the memory card readers... nor can you swap hard drives. Sony basically crippled the lower model so bad that you pretty much didn't want it, so of course it makes the more expensive model the obvious choice for only $100 more, even at a $600 price point. At least with the 360 you have the option of adding a larger hard drive, wireless, and you could add a card reader via usb. And with the new Elite version coming out, it has HDMI, but you can opt to use component with that as well.