When it comes to symphonies i prefer Beethoven, in the piano concerto genre my favourite is Rachmaninov,
string quartets - Dvorak,
string sextets - Brahms,
etudes for piano - Chopin,
piano sonatas - Beethoven,
violin sonatas - Saint-Saens,
piano with strings chamber(piano trios, piano quartets, piano quintets, etc...) - Schumann,
opera - Bizet,
nocturnes for piano - Chopin.
What about all of you?

I suppose that in my case, the ones I like quite often came from composers who only wrote one anyway!

symphonies - Vaughan Williams
piano concerto - Elgar/Walker, also Rachmaninov
string quartets - Moeran
string sextets - can't think of any at the moment
etudes for piano - Chopin
piano sonatas - really can't decide on this one, but not Beethoven, Mozart or Haydn
violin sonatas - Walton
piano with strings chamber(piano trios, piano quartets, piano quintets, etc...) - Brahms
opera - mmm...not an enormous fan of opera...Mozart I suppose
nocturnes for piano - again, not sure on this one

I expect my choices make me a really bad musician and teacher

OK Here goes:

symphonies - don't care
concertos - Rachmaninoff
string quartets - Beethoven
string sextets - don't care
etudes for piano - Scriabin
piano sonatas - too close to call (Haydn/Scriabin/Prokofiev)
violin sonatas - don't care
piano with strings chamber - Brahms
opera - Puccini (sorry for such lowbrow tastes)
nocturnes for piano - Field, Alkan

why concertos/etudes/sonatas/nocturnes, but not:

preludes, rhapsodies, intermezzos, waltzes, characteristic pieces, mazurkas, ballades, ... ??

Symphonies - Beethoven/Mozart/Dvorak/Tchaikovsky
Concertos - Mozart/Beethoven
String quartets - Beethoven
Etudes for piano - Chopin
Piano sonatas - Mozart/Beethoven... and maybe Scriabin. Scarlatti too if he counts
Violin sonatas - Don't know... I guess Beethoven, but there are many isolated ones
Piano + strings chamber - Brahms/Dvorak
Opera - Mozart... then Verdi
Nocturnes - Chopin
(adding some of Mad Tom's suggested genres)
Preludes - Debussy
Intermezzos/capriccios - Brahms
Mazurkas - Chopin
Ballades - Chopin
"Suites" (i.e. multimovement pieces that aren't sonatas) - Debussy

I can't distinguish by genre- while it may seem like a useless contribution, I wanted to say this to give the viewpoint of someone whose head just doesn't work that way

One of my favourite symphonies is Mahler 5, but do I like it more than any of the Brahms? Or than Shostakovich 15? I can't make up my mind! And so it goes for any other genre...

I agree with you completely! I'm just looking for ways to procrastinate by answering a question that doesn't really make sense to me

Symphonies - Mozart
Concertos - Rachmaninoff
String quartets - Beethoven
Etudes for piano - Chopin
Piano sonatas - Chopin
Piano with strings - Mozart (K548 mvt 2!!!!!)
Nocturnes for piano - Chopin, Field
Preludes - Chopin
Waltzes - Chopin
Characteristic Pieces - Grieg
Mazurkas - Chopin
Ballades - Chopin (it is little known that he was creator of the instrumental ballade...)
Polonaises - Chopin

Regards,
Wurlitzer

Symphonies - Brahms and Dvorak

Concertos - Brahms

String quartets - not a fan

Piano sonatas - Scarlatti

Opera - Purcell (if he counts) and Wagner

Preludes - Bach and Debussy

the rest - no clear view.

Interesting idea!

Symphonies : Beethoven (without a shadow of a doubt) though Mahler does come close.

String Quartets : Schubert

Song with Piano : Also Schubert

Orchestra and Chorus : Britten (just for the War Requiem)

Piano Solo : Beethoven again

Opera : WAGNER

Larger Scale Chamber Music : Kurt?g (a Hungarian contemporary of Ligeti)

Violin Concertos : Beethoven AGAIN but to avoid being repetitive I'm also going to say Ligeti and Sibelius

Piano Concertos : Bach (not technically a piano concerto but the D-Minor Keyboard Concerto is astonishing)

Oboe Concertos : Richard Strauss, not that there's much choice.

Misc. Chamber Music : Mozart, for the Clarinet Quintet

Symphonies: Shostakovich
Quartets/Chamber: Shostakovich, Haydn
Songs/Lieder: Schubert and Vaughan Williams
Choral: Arvo Part, Elgar, Britten
Piano Sonatas: Beethoven, Haydn
Organ: Bach, Dupre, Messaien
Opera: I have no interest whatsoever in Opera - they bore me silly.
Concerti (Piano Violin Viola Cello): Shostakovich

I think I like too much stuff....

Symphonies: Tchaikovsky, Elgar, Shostakovich
Quartets/Chamber: Mozart, Haydn, Vaughan Williams, Tchaikovsky
Songs/Lieder: Elgar and R Strauss - I think you know the songs I mean!
Choral: Bach, Handel, Poulenc, Verdi, Rutter
Piano Sonatas: Not very familiar with these, so can't say
Opera: I have only watched one proper opera (on TV ) and I enjoyed it, so Donizetti (you're lucky I've seen that, or I'd have had to say G&S )
Concerti: Rachmaninov, Dvorak

Wow, talk about diverse tastes!!

haha! indeed.

OH - yes, G and S too. Count me in.

Someone has mentioned choral music which was not in the original list. I fear my list would be too long here - starts with Anon. and ends with Eric Whitacre. By way of Tallis, Byrd, Purcell ....... you get the idea.

sorry to go but when we started A level we were given an anthology of about 20-30 pieces and were told to go away and write a paragraph or two about all the composers in the list. The next week my friend Sally came to the lesson quite upset and told the teacher that she hadn't been able to finish her homework... she'd looked everywhere but couldn't find anything about a composer called Anon....

...me too!

How about Ibid and Trad?

Ravel for chamber music!