I've been working on-and-off since 1993 (when I was aged 15), and have experienced about three major "outbursts": 1993-98 (everything handwritten, BTW), 2003-2005 and 2011-2014. I've also revised or reconstructed earlier works, so my current catalog sits at around 40 pieces with assigned Op. numbers. I tended to believe that most of them were either orchestral pieces or solo piano works, as I feel most at home in either environment - but I've realized that most of my output is actually chamber music.
My piano pieces include 5 Sonatas (most of them earlier pieces, excepting the single-movement Northanger Sonata Op. 25 and my Op. 37), as well as three smaller collections, the Romance and Variations Op. 4 and a couple minor works.
My complete orchestral output consists of 4 orchestral suites (including standouts Aurora Op. 12 and Adriana Op. 27), 4 symphonies (of which I regard the 2nd as the best, although I'm currently revising all of them), and 7 overtures & symphonic poems (best represented by Emma Op. 31 and El Cadejos Op. 38), as well as two concerto-like pieces for soloist and orchestra (Op. 34 and 35a), both of them under revision, and some fragments.
The chamber pieces are the most diverse. My favorite one is the String Serenade, Op. 11 - but I also have 2 string quartets, 2 piano trios, an additional trio for flute, clarinet and piano, a violin sonata, a collection for flute and strings, 2 smaller works for strings and a minor early work for piano and trumpet, plus solo works for cello and tuba and a few arrangements. These make up more than a third of my total output, actually.
I have also written a couple vocal pieces (a song cycle and Jabberwocky), but no choral or stage works so far (although some of my Suites could be easily transitioned into ballets).
As for your last question, that's a bit tough for me to answer. I have too many projects for my very limited available time, so despite having a few pieces under "revision", I can only commit to one at any given time. So I try as hard as I can to finish that particular one before moving on to the next - unless the "next" idea is so powerful that I can't push it back anymore. So I might fall on either Noah's or Bkho's camp, depending on the circumstances.
Good questions indeed...