The Memory of Whiteness
Kim Stanley Robinson is well known for his Mars Trilogy and The Years of Rice and Salt, but I've read some of his earlier works recently, and while markedly different from his more recent, high-profile works, both The Memory of Whiteness and Icehenge are rewarding, idea-rich reads with complex characters and political structures.
The Memory of Whiteness, his first novel, is particularly unique; Robinson envisions a future where we've colonized most of the solar system, including moons and asteroids. Rather optimistically, Robinson's story is primarily about how important live music is to this distributed culture, and if you can get past that, he's got a bit of whodunit and some genuine cultish weirdness thrown in that makes for a loopy-but-gripping read.
I've also just started his Forty signs of Rain, which is set in Washington DC of the very near future, dealing with the political landscape of climate change legislation. Sounds fun, right?