when i stream/download "HD" episodes/films, they're not really HD are they? in that, the monitor or tv i'm watching it in isnt connected with a HD wire. is there a PC-to-TV HD sort of wire I can buy somewhere to hook up to my tv so the HD things i watch online are genuine HD DVD/blu-ray quality? will it be mega expensive?

i'm not entirely sure what i'm talking about. preperation for the last ever LOST (omg) really.