I'll add some stuff that I've been digging or maybe some stuff that slipped through the cracks.
1-The Irresistible Force-Flying High. Maybe the definitve mid-90s ambient album from the rave generation. Mixmaster Morris serves up the psychedelic weirdness on this winner. Sampling everyone from Cage to Stockhausen. Even comes with instructions on the proper way to listen. His other other albums Global Chillage, It's Tomorrow Already & Dreamfish(with Pete Namlook) are also highly recommended.
2-Shpongle-Are You Shpongled? Another psychedelic masterpiece that sounds like The Orb making ambient Goa tracks. BRILLIANTLY PRODUCED and sounds simply HUGE on a great system.
3-Steve Reich-Music For 18 Musicians. Hypnotizing is the best adjective I can come up with this which is by far my favorite Reich piece. Coldcut claims that this is their very favorite piece of music ever. That's a good thing. One of only a handful of albums that I MUST listen to in its entirety.
4-DJ Shadow-Endtroducing. This one should be subtitled "Hip-Hop Album For People Who Hate Hip-Hop Music". Entirely sample-based masterpiece is both timeless and innovative. If you're a fan of old-school funk or r&b(by r&b I don not mean New Edition or Keith Sweat) then you'll dig this one. Obscure as almighty hell breaks and beats are abound. Funky drummer break on this album? Uh.....NO! Even the semi-obscure breaks are nowhere to be found. Still sounds fresh after almost 10 years. I have listened to this album at least 500 times and I still pull it out once every few weeks. Essential. Oh yeah...There's no rapping on this.