I won't say that the 4-5-1-2-3-6 method has no merits. It's interesting, and a lot of the arguments for it are valid.

However, for someone who's never before seen Star Wars, I'd have to say that there is only one way to show it to them:

Star Wars (1977 or 1981 version)
Empire (1980 version)
Jedi (1983 version)
Whatever the hell you want to watch after that, if any at all.

And my #4 means that, if after watching those three, they want to watch the prequels, great, go for it. If they want to watch the 1997 or 2004 SE's, go for it. If they want to watch the Clone Wars cartoon series (either one), go for it.

My point is, the originals should be seen first by anyone who's never seen the films. That's how I watched them, and that's the only way they could be watched for 14 years.

Saying you should watch them in any other order is like saying you should read Brian Herbert's Dune prequels before you read Frank Herbert's original novel. It just doesn't work.

I think the 4-5-1-2-3-6 order should only be used once someone has seen all the films, and wants to watch them in a new perspective. In that context, it's a great method. I'd never suggest that someone who's never seen any of them should watch them that way, though.