It depends. If you're going to be submiting it to a con then go for the Japanese audio track. If you're going to be inserting the dialog in the middle of the video without changing the volume of the song, it would probably be best to forgo the addition of subtitles. If you're going to be inserting a little scene at the end of a video, for instance, then go with the subtitles.
Now, if you're not going to be showing it at a con, then you can use the English track (provided it's a decent dub) if you want. Sure, the purists will be all over you, but they need a life so they don't count. It just makes it easier for the general public to understand what you're going for.