He was an extremely prolific composer, a unique quality in the twentieth-century. As a result, however, I've had trouble finding a work that I really identify with. What I've heard is all very fun to listen to, but I haven't heard anything just yet that really sticks. That said, both his fourth symphony and fourth chamber symphony were great works. I'm not sure which I prefer. The fourth symphony has frequent use of percussion, which I love in orchestral works, and doodles on some marching tunes, but his fourth chamber symphony sounds much more vibrant, inspired, and lively. The two were composed about twenty years apart.
Definitely worth the listen if you're interested.
Anyone else listen to Telemann of Quantz?
Holy shit he has a shitload of quartets! I will have to look into those, yeah. Another prolific composer I can think of from the same period is Bohuslav Martinů.
Iannis Xenakis' scoring actually really pissed of the Kronos Quartet and played a role in their departure from atonal music for minimalism. Thanks for the links, incipitsify's video of George Crumb's Black Angels was the video I watched a few months back. Though his scoring is conventional, it's not impossible to read like some others' are.edit2: I have to say, there were quite a few great 20th century Czech composers. I suppose it could be argued that they're "behind the curve" on modernism, but that's a crap argument. Musical perception is relative.