rings of death happen beacuse motherboard keeps bending over time due overheating,which leads to desoledering connections and other nasty stuff.horizontal poz. improves air ventilation.do not use intercoolers and dont put usbfans at the back of your console,as those things only speed up air circulation so air inside console dont have much time to pick heat from heat sinks.your best bet is to leave console as it is in horiz poz, in well ventilated space,protect it from dust and if your console survives warranty period do what i did.open it,apply proper termalpaste(AS5),clean it from dust,and invest in some heatsinks for memmory,extra fan in front gpu so it sucks air from backpanel, and replace fans at the back.console will be cooler inside,and i promise heat wont kill your 360.

360 is great system,cheaply made,with terrible cooling system,but atleast games are worth it:)