this is how I see it at the moment
JUMP UP
basically split into 3 categories, hardcore wobble (nu school very very wobbly kool fm-ish sound) 'pro wobble' (think hazard, g dub, taxman etc) and commercial sounding jump up (think sub focus, culture shock, TC)
LIQUID
split mainly into 4 categories as well, there is the new influx of quite sparsely arranged but subtly well produced stuff (think lynx, alix perez etc) not sure what this is called
then there is your cheesy liquid from the hospital camp (think fatter snares and more obvious melodies from people like high contrast and danny byrd and perhaps Brookes Bros)
then there's calibre, in a league of his own imo
Finally there is very atmospheric liquid which isn't really being made so much anymore, apart from the likes of ASC etc, but which was introduced really by people like Bukem and PFM in the nineties. Think very atmospheric, long, slow moving tracks.
DARK
With dark dnb you have Neurofunk (big snares and fucking well produced basslines, think Noisia, Phace, Spor etc)
Bassliney simple stuff from people who tend also to make liquid tracks (spectrasoul, icicle, alix perez etc) and these are usually simple but effective and mixed in with liquid tracks
Drumfunk from the likes of Fanu and Paradox, not really about the fat snares or big basslines but about chopped up interesting drum samples and atmospheres.
Then there's your really dark-step which is interesting because whilst I'm quite into this sound, artists other than Current Value and Limewax tend to not amaze me so often, seems as though these two are leading the scene with the help of people like Donny and Dylan. This sort of dnb usually has very intruiging rhythmic patterns and nutty basslines, and is usually pretty noisy. I think it's an aquired taste...
...that's the way I see dnb at the moment, probably forgotten some types though...