which order to watch the movies would you suggest?

I planned to finally watch all the Star Wars Movies. (Up to now I've only seen the episode one, but that's quite a while ago) Should I start with 4,5,6 then 1,2,3 or 1,2,3 then 4,5,6?

maybe spoiler: i know that the young one from the first episode becomes darth vader...

excuse my noobism, better late then never