Harrumph, stumbled upon this thread; it's old, but as a gigantic classical music nut who's listened to most of Mozart's works, I just really want to reply.
I want to thank Philosophyking87 for defending Mozart since he is also one of my favourite composers, among Bach, Beethoven, Mahler, Strauss, Händel and Wagner.
The first thought I had was that most people probably haven't heard enough Mozart to judge him properly. Mozart equates too often to
Eine Kleine Nachtmusik, which I'm personally fed up with, and a few other pieces, perhaps Symphony No. 40. I think the former is a bit of an unfortunate piece to identify Mozart with, as I always found it to be a bit generic.
As with most great composers, there are more facets to him than those pieces, though: If you like Bach, try the Jupiter Symphony's last movement (Symphony No. 41), which is a massive fugue; if you don't like his enthusiastic playful, child-like music, you might enjoy the
Commendatore Scene or the
Overture of
Don Giovanni, or parts of the
Requiem and
Great Mass in C Minor. Another of my favourites is the slow movement of
Piano Concerto No. 23.
Although I have not studied music, I think Mozart is one of, if not
the greatest inventor of melodies in the history of music. Among my favourite composers, only Strauss's
Last Songs come close. Beethoven is the master of variation: he will mostly use only a few tunes and brilliantly present them; Schubert is similar. Mozart was not as skilled in variation, but could come up with new melodies seemingly at will.
If you think Mozart is generic, by the way, try to guess what comes next in a (good) piece you don't know. In my experience, and in stark contrast to contemporary composers like Salieri, you won't get far. Mozart's music is deceptively simple; many people, including great musicians, fall for it. Here's an excerpt from an interview with Friedrich Gulda, an Austrian world-famous pianist:
At the same time, these public concerts marked the beginning of a new-found love of Mozart. In an interview with the Munich Abendzeitung prior to his Munich appearances, Gulda declared that until then he had "misused Mozart by treating him as a pianist suitable only for warming up and for playing while latecomers are taking their seats. In my old age I have become conscious of this mortal sin - and have drawn the necessary consequences from it." Gulda immersed himself in Mozart in a way that he had never done before. "I've been preparing for this for a long time. I wanted to know how this music feels. I can now say that it feels marvellous. Stylistically speaking, there is no doubt about it." Until then, Beethoven and Bach had been central to his life. Now it was Mozart, with whom Gulda felt an increasing empathy. He spent his whole life working on this music. "Herr Mozart", as he affectionately called him, became his omnipresent model and guide. And towards the very end of his life, Gulda declared that when he was dead, there was nothing more he could wish than to play piano duets with Mozart on a pink cloud.
Also, in my experience, no other composer can convey joy and happiness as well as Mozart. Bach can sometimes come close. Beethoven is very motivational and powerful but not necessarily joyous, although he can be very humorous (try the
5th Piano Concerto, "
Emperor", especially fun with Gulda).
Mozart deserves to be called one of the greatest composers, I think that is beyond doubt. He is more popular in the media than the other great ones, but seeing how superficial that fame is, I wonder whether that is really something to be annoyed about. It's also a bit unfortunate, I think, that
Eine Kleine Nachtmusik is the single most exposed piece; Bach was luckier there with his Air, and Handel's
Zadok the Priest (used for the Champion's League) is also of higher quality, in my opinion.
Had to get that off my chest! :-)