Dear YunaX, it will definitely be a good idea. You get to play with your Xbox360 without your parents or housemates fussing about wanting to watch the TV, so you get personal privacy. Please obtain a genuine XBOX360 VGA cable though to ensure you get the best picture quality. There have been reports that some plain cheap third party cables gave bad image quality and all sorts of problem.

This doesn't mean better third party products isn't good but there are a few types packaging available for the exact same thing so you have to be careful. For example, you'll need a female-to-female connector to change the cable terminal gender to support your 17" computer monitor. However, this is only required if you monitor has a video cable attached permanently. Newer LCD monitors has a detachable video cable so this is not required. The cable can be connected directly.

Then again if you're using your computer speakers or built-in monitor speakers for sound reproduction, you'll need RCA-to-stereo plug converter. This is not needed if you're connecting to a standard AV equipment like an amplifier though.

That is why I suggest you get a genuine XBOX360 VGA cable because Microsoft took the liberty to include all these accessories in the standard package, saving you from the fuss of looking for them individually. The RCA-to-stereo plug is available at any electronic store, however the female-to-female 25 pin D-sub connector is a pain to find because it is not a common part.

I've been around Sungei Wang and none carries the original package. Some claim to carry them but they do not look like an original even though the packaging is very similar. So be careful. Fortunately, I went to Gamers Hideout at CineLeisure and they do carry this product selling for RM99 if I'm not mistaken. So you might want to shop around.

Ok back to your original questions. The XBOX360 can definitely render in 4:3 ratio. You need to specify that you're using a normal monitor instead of widescreen. Then you need to choose a resolution that is both a 4:3 aspect ratio and closest to your native resolution. If you're using a 17" LCD, I guess it should be 1280x1024. If its a 17" CRT, then it should be a 1024x768. Some games especially video feeds cannot support 4:3 so you'll be viewing in letterbox mode but during gameplay your GPU should have the freedom to render in whatever resolutions in whatever aspect ratio provided the game code supports it.

Playing XBOX360 on a LCD monitor depending on configuration would results in slightly washed out colours compared to playing with component on HDTV. This is a known problem and there is not fix as of yet. This can be fix or workaround by adjusting your monitor or doing a simple calibration.

Hope this helps.