Graduation for me. Singles were incredibly strong IMO (Stronger, Good Life, Can't Tell Me Nothing, Flashing Lights), the sound he cultivated on that record was the peak of his boom-bap/Dillaesque adventures into production on tracks like The Glory and loved the features outside of Wayne. LR and CD are up there but Kanye raps better on Graduation and I find myself skipping less tracks, 808s was trash and MBDTF has way too many guest features tucked between the moments of greatness. After that record Kanye turned into an overly conceited weirdo and started working with all these wack artists sans Jay in lieu of Mos Def, Common, Kweli, Lupe, Dwele, etc.
Graduation also dropped at a great point in my life so that kind of association with that record still hangs with me as well.