First i played Kotor ,got hooked up on SW then i watched more carefully episodes 1,2,4,5,6,3,in that order.
It is sad that most of the younger ppl now watches it in episode order. The films should be watched in release order. The original trilogy story structure was designed and written in way that you start with Ep4. The prequel trilogy as its name clearly indicates is a back-story to original trilogy so it should be watched second.