Playing devil's advocate here, there is a danger of dumbing down the tradition, both of folk music (whatever your definition) and of the music from other roots.

That said, most of the 'genres' in the Levellers original post can trace their roots back to the traditions of the British Isles, so a fusion works well in most cases. Love Bellowhead, and many of the other acts listed in this thread, but from a purely personal viewpoint, I don't like the fusion of english tradition with indian or afro carribian music. Went to see Edward11 once, but left during their third song, the combination of a reggae band and a squeezebox just didn't do it for me.

Can't be too precious about it though, as I am having the time of my life persuing a plan to grow old disgracefully fronting The Bounty Hounds folk/rock band, which does seem to be attracting the right sort of attention.

John