For me, I'd say Sgt. Pepper. Every track is perfect, and just listening to the record can transport me to another place, just like a good book can. I honesty get this effect from a few Beatles records, but Sgt. Pepper does it the most.
Who's Next is another one for me. It was the soundtrack of my high school days (even though I was in high school in the 90s), and I consider it to be the zenith of one of my all-time favorite bands. Another everything-is-perfect album.
What about you guys?