I should have been more clear. I'm actually looking at DVD Recorders for home AV, not a ROM for the PC.

But your descriptions of the formats still apply, so thanks for those. I had gotten an impression that compatability was a big issue with these formats, but for my uses I'm not really concerned with compatability. I'll most likely only be playing my discs on the recorder I end up buying, so I'm not sure which one to go with.

Now as for those formats, I've read that you can edit a DVD-R disc, but only before it's finalized, after which it is uneditable. So what are the RW discs?