I gotta say my favorite stuff from the US is Trait/Lunde (for those unfamiliar all the stuff on IR is def a good place to start), Hands To (Forced Nostalgia put out a nice DVD with all his work) if I were going to pick one I'd say Egress (though recent work under his own name is great) and the other acts associated with incubator/YC. I'm also constantly blown away by the work of Joe Colley/Crawl Unit, the recent LP on Glistening Examples is a must for anyone into that kind of sound.
more recent people putting out incredibly good work and performance would be Dilloway, Wiese and Lescalleet (though all have been around for a bit). Those three though I am consistently impressed with.
Older acts that I think are standout and historically important
Smegma/LAFMS, TLASILA, Haters, Macro and Emil
