I think this is really splitting hairs. For me it hinges on the reveal at the end of ESB where the prequel trilogy falls

I know what you mean. It would be nice if you could watch in an order where neither of the big two reveals get spoiled (near end in 3 and end in 5).

First time: IV, V, VI, I, II, III

My preferred order: I, II, IV, V, III, VI

Now that's interesting. Two two movie buildups, then the climaxes. Not bad at all.

I'd go I-VI with the older Clone Wars animated movie between II and III. I'm not sure if it is cannon though... originally I think it was but then they did a 2nd CGI series (which I never saw much of) so I'm confused.

As for spoiling the "reveals" of the series if you watch them in numerical order... what adult born and raised in the United States under the age of 40 has not heard of them before? It's like someone watching the first episode of Star Trek today for the first time and being amazed after Kirk survives each near death encounter. Who doesn't know that Kirk was the main character in the rest of the series as well as like a dozen more films?

I watch I, II, Clone Wars Cartoon, III, IV, V, VI