I haven't rewatched all the movies myself but when I do, and I hope I will with my son at some point, it will be in Machete Order (so named because it was first described on the nomachetejuggling blog).

The explanation why is full of spoilers and you can find it online. In short, it takes the journey of one soul, reexamines it through the story of another, then joins the stories in a grand finale.

The order is: IV V II III VI and then episode order from then on. It papers over some of Lucas's worst narrative mistakes and ruins none of the surprises except one.

If this seems silly, then release order. The prequels require original trilogy (TOT) knowledge to fully enjoy, and they ruin important surprises in TOT, so episode order is just not the way.