I like some grindcore, Napalm Death, Carcass, Cephalic Carnage, Discordance Axis, Genghis Tron, Uncle Bob Drives a Combine, HeWhoCorrupts, Pig Destroyer, Graf Orlock, (just to name a few)
Old school Napalm Death like SCUM and FETO are very brutal and primitive, but they have their moments. Fear Emptiness Despair, was kinda of a refinement of those earlier albums, more groove and less chaos. New grindcore bands like Pig Destroyer and The Dillinger Escape Plan, throw the kitchen sink at you, mixing thrash, death, industrial and even metalcore. It's the best metal genre going these days.
I agree with metallideth, though recently the songs I've been liking are those of Agoraphobic nosebleed.
I'm sorry. I seem to have given you the idea that I'd like grind if it had melody. My bad. How's this for elaboration: I like music with melody, or at least a suggestion of melody, which is not too in-your-face, with as little technicality and breakdowns as possible, has a continuous stream of high-end fuzz for guitar, and preferably a lousy production. Psyopus, or grind in particular, is not it. I tried a few songs from their myspace page, and, well, no thanks. Hooks and breaks and OMG240BPMUBERBR00TALITYFTW do not make my penis swell up in glee.
I'm the guitarist for a band that plays mostly grindcore and mathcore... Very expressive and passionate... i wouldn't venture to say its a lot like a new form of jazz... but the feel for seemingly random notes and composure is there, it feels great. P.s. I'm also a drummer for a old skool punk band....