I recently rediscovered the pure musical genius of Nine Inch Nails. My first memory of listening to their stuff was Chris Eidse's Pretty Hate Machine tape back in 1991, and it was a bit of a revelation -- I dubbed it from his original cassette and played it to death. I've only collected 20 or so songs since then, but they're unbelievable -- harsh, abrasive and challenging, but also beautiful and intricately crafted. Time to dig into the entire canon, methinks.
Also getting lots of airplay on my headphones lately: Radiohead and Thom Yorke.