well component IS really good for picture quality. Don't forget to fiddle with the needed settings on the Xbox AND the panel in case of using the VGA.The panel has settings regarding the VGA input that makes you think that is a computer monitor.
The image quality between 720p and 1080i is almost the same. So you could set the xbox for 1080i too and have a great picture also.For now you can have a blast with the Xbox360 and the component, and later on you can see how it is with the VGA too.
EDIT: Well there are all sorts of cables and adaptors to custom fit your needs: For example you can connect the PC to the HDMI port ( the panel SUPPORTS PC over HDMI, you can even choose the colourspace between HDMI-PC and HDMI-AV ).
Then you can connect the Xbox to the DVI usind DVI to DSUB adapter.
About the PS3 , well we'll have to wait until it comes.For now there is no other panel that comes as equipped as this one. 1080p would be nice, but I love the image quality I get and espetially with digital sources. I would like firstly to get enough of 720p and 1080i , so...
About the real estate on lower res : The panel is like a PC LCD monitor. There is no lack of the real eatste in lower resolutions, the image is scalled to fit the screen and it does so in an exellent way.