Omfg don't get me started on Animals. :0
Wish You Were Here by Pink Floyd is definitely a good one and is a high one on my list, also Animals, Led Zeppelin II, Dark Side of the Moon, Moving Pictures by Rush, hemispheres by Rush, Paranoid by Black Sabbath, Abbey Road by (you know the answer (i hope)), Gish by the Smashing Pumpkins, Siamese Dream by the pumpkins, as well as Mellon Collie and the Infinite Sadness.
However, the two that I probably listen to on a weekly basis are:
1. The Wall by Pink Floyd. A bit mainstream, but it is truly a great album. For starters it is a HUGE album with a ton of songs, and they are all so different. With that, I like to think of it as a very.. Flavorful/colorful album. However, the album also tells the story of a boy named Pink and his unfortunate journey to the music industry. Truly a fascinating album to listen to.
2. Demons and Wizards by Uriah Heep. I doubt more than 10 people on this forum know of this album, but it is a highly underrated one and is a true jam. If you want a definition of the 70s, listen to this. EVERY song on this album is at its best potential. Good to listen to when working/doing homework/things around the house. You can't get better. :)