I'm never sure why people ask for listening advice. "Just explore" would be my first response, followed quickly by "why 'major composers and works'?"
Then, deftly dismounting from my hobby horse, I'd recommend you look for labels. A lot of the old school stuff is on Neuma. They even have a numbered series "Electroacoustic Music I, II, III, IV," and so forth. Wergo has put out a lot of stuff, as has col legno, Cybele, Mode, and Lovely Music. Centaur has a huge selection, mainly American. Metamkine has a huge selection, mainly French. emprientes DIGITALes has a huge selection, largely Canadian. All three are international, though. And speaking of international, the Bourges Festival, now in its 38th year, puts out CDs every year, of the festival and other things. Best way to get these now is directly on their site at imeb.net.
And speaking of sites, the Canadians have a sweet site of electroacoustic concerts for your listening and downloading pleasure. These are mostly the emprientes DIGITALes folks. Perhaps solely. That's at
http://iconcerts.rien.qc.ca/.
There are tons of smaller labels that do electroacoustic and live electronics stuff. Ground Fault is one of the bigger of those, but you should have enough now to keep you happy for years. Sonic Circuits is another festival that's documented on CDs. There are maybe eleven or twelve now, I've lost track.
