Just spotted your old post and feel I have to recommend Smetana. The two string quartets are great, and he did a fantastic piano trio as well. Very powerful stuff! Also, when I was looking these up I found my Brahms and Schumann piano quintets; oh, and Mendelssohn Octet; oh and do give the Beethoven quartets a listen the Lindsay quartet version (the later ones do it for my. I'll go now...