Hard task...and gets harder the longer you live and the more new (or old) stuff you discover and embrace.
Dark Side will always be #1 for me...the lyrics, the production, the precision of the music. The rest is not really in order...and I did 15:
1. Dark Side of the Moon, Pink Floyd
2. Wish You Were Here, Pink Floyd (best 5.1 mix my ears have heard)
3. And the Glass Handed Kites, Mew
4. Close To The Edge, Yes
5. Tales of Topographic Oceans, Yes
6. Houses of the Holy, Led Zeppelin
7. Physical Graffiti, Led Zeppelin
8. The 1971 Fillmore East Recordings, Allman Brothers (cheating here a bit)
9. Achtung Baby, U2
10. Fate of Nations, Robert Plant
11. On An Island, David Gilmour
12. Exit...Stage Left, Rush
13. Songs from the Big Chair, Tears for Fears
14. The Beatles, The Beatles
15. Blade Runner Trilogy (soundtrack), Vangelis
I could easily have two or three more Zeppelin albums in that...I did name a daughter Paige after all. Six or seven years ago I think it would have been Zeppelin's first album rather than Houses, but tastes and ears change I guess.
And...while I always enjoyed The White Album, it's just recently with Giles Martin's recent remastering that I find I really love it and appreciate it's special genius.
Strict top 10 if limited to one per artist and also prohibiting solo works from listed artists:
1. Dark Side of the Moon, Pink Floyd
2. And the Glass Handed Kites, Mew
3. Close To The Edge, Yes
4. Physical Graffiti, Led Zeppelin
5. The 1971 Fillmore East Recordings, Allman Brothers
6. Achtung Baby, U2
7. Exit...Stage Left, Rush
8. Songs from the Big Chair, Tears for Fears
9. The Beatles, The Beatles
10. Blade Runner Trilogy (soundtrack), Vangelis
Best year for music: 1971. Who's Next, Zeppelin's fourth album, The Yes Album AND Fragile(!), Meddle, aforementioned Allman Brother's at Fillmore, L.A. Woman, Sticky Fingers, Electric Warrior (T Rex), Imagine, Stormcock (Roy Harper)....wow, what a year!