I use dvd2one to make my video backups, and I was wondering if I only need the 6channel audio stream or if I need both 6 and 2 channel audio streams. I watch dvds on both my home entertainment system that has a dolby and dts decoder and also watch movies in the kids room where they only have a ps2 with 2 channel rca outs.

You only need the 5.1 channel. If you are copying DTS however, you will have to have a dts decoder to hear sound on these movies

So I only need the first option, which is 6 channel english. And I don't need the other option which is 2 channel english, right?

You only need 1 sound channel mate, some films only have 5.1 and they wouldnt do that if they would only play on certain players would they, any dvd player can handle 5.1, if you want 2.0 also you can but you will loose quality.