I have only heard of the last three bands you mentioned, and seriously I NEED to hear something by Husker Du and Fugazi sooner, rather than later.
Holy shit, Nerdcore? Really?
You also totally need to hear Big Black, and not just because they have an album called Songs About Fucking.
And YES. Apparently there are a whole bunch of rappers who rap about ... nerdy things and it's been added to RYM as nerdcore with "geeksta rap" as an aka.
Speaking of genres, what do we have here?
It's synth pop.