i wouldnt go putting mr scruff and aphex twin and kraftwerk in the same category. but hey. and isn't illbient just a word dj spooky made up and no-one else uses?
so, in conclusion: i got nothin'. let's just abolish the genre system entirely and replace it with "awesome" and "not awesome".
Yeah, I guess Mr. Scruff is closer to fusion/triphop; Kraftwerk is closer to house; and Aphex Twin is closer to ambient. But none of them fit within those genres, so I thought - hey! - throw them all in. And, yeah, illbient is shit DJ Spooky made up. Threw it in because quite frankly for the hell of, and because I think it describes "instrumental hip hop" a lot better than the phrase "instrumental hip hop" -- which is almost as retarded as IDM.
I think that the genre system is essentially irrelevant at this point, since the whole independent electronic and indie rock scene is one that defies formalism and voluntary categorization. This is hardly profound, but the only useful reference these days is other bands: you've got some focal point bands that are used as descriptors and pretty much act as modern genres.
But you have to have some way to describe a group that someone hasn't heard other than "awesome" and not "awesome". Genres or other routes of description aren't just all about being a know-it-all music nerd cock. Just like, 90% maybe.
Also about Mr. Scruff, I was thinking more about the older Mr. Scruff like on the Mrs Cruff re-release, and less about, say, Trouser Jazz.