Makes me curious what Nostraman music would sound like... (assuming they cared for that kind of thing).

I'm sure Nostramo had its fair share of gangsta rappers.

Ah, yes I can see it now... Rap battles of 40k Sev vs Curze 3.. 2 1 GO

Dub step, raves

I will give my two cents about that.

Nostramo have been depicted as having a Mafia like society feel. I'd look at music originating from the society who spawned the top five group of Mafia, ( Sicilian Mafia,American Mafia,Russian Mafia, Albanian Mafia,Yakuza). As a example , Nostramo Quintus is pretty much a very dark and twisted Gotham City of 40k. Gotham itself been inspired by various city under the influence of American Mafia (Chigago in 1940s, then shifting slowly to intertwine with NewYork of the 1960s and 1980s). Hope it inspired you .

yeah, i could see that

Beside who would not gear up the old warplate and bolter under that theme .

I am picturing a landspeeder picking up a bunch of Night Lords and raiding supply routes by performing Drive-by's in slow motion.

The language is Nostraman. Minor nit-picking.
I've always imagined Nostraman artists to be like their homeplanet. Dark, moody, gothic. So, musical genres like classical, horror-rap, maybe aggro-tech would be very much the norm. Paintings, would probably be very dystopian, or macabre themed, like the real life Polish artist Zdislaw Belsinski. Sculpture, architecture, masonry - this would all be like the rest of the 40k setting. Gothic architecture, but cranked up especially so on the planet Nostramo.

...at least how I imagined it.

http://ukitakumuki.deviantart.com/art/In-Midnight-Clad-470384556