I’ve been listening to a lot of chamber music on XM radio. I’d love some suggestions of some works to try. Over the past few days I’ve heard:
Faure: Piano Quintet no. 2 in C minor
Haydn: String Quartet no. 20
Schubert: I didn’t quite catch the name…the Sunrise quartet?
Mozart’s Eine Kleine Nachtmusik might not be chamber musik.
Beethoven has many string quartets and such that I have enjoyed. Some woodwind stuff too, of course. 
(disclaimer: I mostly listen to 20th-century classical)
I love the Fauré piano quartets (the quintets too, but you listed that). There’s one in C minor and one in G minor.
For string quartets, my favorites are Hindemith (he wrote 7), Bartok (6), and Shostakovich (15). Also Debussy and Ravel, who wrote one each.
Any of Poulenc’s chamber music is fun. I like the sextet a lot, and the flute sonata is one of those pieces that gets horribly stuck in your head but it’s okay because it’s good.
Milhaud’s Suite for Violin, Clarinet & Piano is a fun piece (influenced by jazz).
I"m fond of Mendelsohn’s piano trios – I think #2 is my favorite but I could be wrong – I’ll have to go look those up.
For a lovely string quartet, you may not believe it, Ives #1 written while still a student (and presumably to please his instructors). Personally I prefer #2 by Ives, really exciting stuff.
I don’t know of a Schubert quartet by that name, but Haydn’s string quartet Op. 76 No. 4 is nicknamed “The Sunrise.” After a little Googling, I learned there is a string quartet (i.e. a group of four musicians) named the Sunrise Quartet; perhaps they were the performers on what you heard?
Anyway, the Trout Quintet is Schubert’s greatest hit in the chamber music genre, and one of the most popular pieces of chamber music by anybody. He also wrote some popular string quartets (including the “Rosamunde” and “Death and the Maiden”), piano trios, and an octet.
Haydn wrote a lot of good string quartets. The six that make up his Opus 76 are probably considered his best, but personally, I like his Opus 64 quartets, especially No. 5 from that set (“The Lark”).
Another Chamber Music Greatest Hit is Dvorak’s “American” string quartet. It’s good, catchy stuff, but he also wrote a lot of other chamber music that’s well worth listening to.
I rather like Schumann’s piano quintet and piano quartet.
I second ErinPuff’s Faure and Poulenc suggestions.
If I had to pick a single favorite chamber work, I might go with Beethoven’s Archduke Trio. He wrote some other great chamber works, too; don’t neglect his violin sonatas. (Interestingly, one of them, the “Kreutzer Sonata,” inspired a story by Leo Tolstoy, which in turn inspired a string quartet by Janacek.)
Thudlow is giving excellent advice. I can’t really add much to that except anything Mozart did in the K400’s and higher is very good.
Im a big fan of the
Bartok - Sonata for 2 pianos and 2 percussionists
Crumb - Music for a summer evening
Brahms Horn Trio.
Messiaen - Quatuor pour la fin du temps
Stravinskys - l’histoire du soldat
Add Stravinskys wind octet to that list…
I knew I was forgetting something on my list!
I really love Schubert’s String Quintet in C, d956; there’s a very nice recording of it by the Lindsays on the Hyperion label (I think).
I’m a traditionalist. I love every movement of every one of Bach’s Brandenburg Concertos. I also highly recommend Mozart’s Clarinet Quintet in A.
Maurice Ravel’s string quartet is great. The last movement will knock your socks off.
The Emerson Quartet’s take on Bach’s “The Art of Fugue” is utterly wonderful.
Please allow me a teeny hijack…
I was in high-school orchestra with the cellist from the Eroica Trio.
(I played viola. Badly.)
Dvorak’s Piano Quintet no. 2 in A Major, op. 81.
Also, his String Quartet no 12 in F Major
The Juiliard Quartet has a CD with both on it – well worth getting.