I would recommend, like everyone else, Harmy's editions if you want something close to the original, but Adywan's, if you want a better special edition than the one we got and something that helps tie the OT and the PT together, visually.

As for the PT, I enjoy watching them occasionally, but don't think they really add much to the saga, storywise (in fact, storywise, I think they detract from the saga). Visually, however, they're a fun addition with all the new planets, environments, spaceships, and of course the war aspect of it.