If you're buying an Xbox360, Please don't buy a modded one as you'll be missing out the wonders of Xbox Live (FYI, Microsoft will perma-ban you if detected you have a modded xbox360). One of the best features of using Xbox Live is downloading content, play your games with people around the world (Guitar Hero 3, Call of Duty 4 and Halo 3 were MADE for Xbox Live) and unleash the full potential of your xbox360.

Get it from Gamer's Hideout in Cineleisure. They offer it at a very good price and also have warrenty service direct from Microsoft Singapore via a partnership with them.