Gaffer Tape said:

Yeah, see, for me it has less to do with spoilers in the 'OMG SPOILERS!' sense, but more just in a narrative build sense. Sequels are always attempting to build on what came before it. Even if it's not even necessarily intended to, it's impossible not to. So, quality aside, each Star Wars movie is building, in scope, in spectacle, in new content, upon what came before it. So the prequels are always going to be made with the original films in mind, but not the other way around. The PT always refers back to the OT because, even though it chronologically comes before it, it was made afterwards. The PT was made to be watched after the OT, and George can whine and stamp his foot about it all he wants, but that's exactly the way he made them. He made absolutely no attempt to make them work in numerical order (although, as I said, that would be practically impossible even if he had tried) and every attempt to make them nod vigorously at the OT. Really, you're putting both trilogies at a disservice to watch them in that order because you're taking away from both of them what makes them tick: for the OT, the freshness of brand-new ideas, and for the PT, the context it's constantly making references to. Again, that's just the nature of the sequel business, and why would you watch three sequels before the original film?

Certainly; spoilers are probably just the worst example of what can happen if you already know ahead.

Maybe it's just how my mind works, but I can happily "blend out" something that happens in a sequel, or prequel, or later in the movie, for the sake of the moment. But blending out something you know about an upcoming surprise, well - it works to 5% maybe.

So I guess if I'd watch it in chronological order, I'd still be able to absorb ANH and all that from the context of its own narrative, without giving the prequels much thought.
I mean, it's pretty obvious from the movie that it was created as a stand-alone, so that makes it easier.