I love Brahms music. After Beethoven, Bach, Mozart and Wagner I would chose Brahms among my 5 favorite composers.
Above all I love his chamber music:
The 3 violin sonatas, the clarinet sonata opus 120/1 and the version for viola of the opus 120/2, the piano Trios, the Horn Trio, the First and 3rd piano Quartets, the 2 string quintets, the First Sextet and, on the top, the extraordinary Quintets with piano and clarinet.
Also love some of his piano music: the 3rd Sonata, the Händel Variations, the last works (opus 116 to 119).
For the rest, Ein Deutshes Requiem, Schicksalslied, the 2nd piano concerto, the violin concerto, the Tragic Overture, the double Concerto and the 4th Symphony.
The Lieder are not among my favorite works.