i dont have a favorite genre of music so in order to not completely spam the thread im going to limit this to 1 each.
aphex twin - 4
i still dont really know where to put him, but i listen to that song at least once a day and it never bored me in all those years.
glenn miller - in the mood
probably the most popular swing tune anyway, but whatever, love it or leave it. best played on a good phonograph.
the pixies - where is my mind
the one song that even those without any affinity to indie stuff should know. and a brilliant piano version while im at it.
bad company - the nine
i never figured out why i cant enter a station without earplugs yet just love listening to this on max volume for hours on end. people with an aversion to excessive repetition and bass might however be better off not looking it up.
max bruch - violin concert nr 1, op. 26
in my opinion the best piece for violin ever written. i read he himself hated it for it became the only one he was known and acknowledged for and people always just wanted to hear this one masterpiece, but i cant help it, way too genius. the only classic work i hold dearer than that would be tchaikowskys nr 6 which has already been mentioned.
pink floyd - comfortably numb
my first true love so to say, very psychedelic but definately the most well mixed album i ever heard. and the second guitar part towards the end of that particular song is just insane.
the mars volta - eriatarka
progressive rock, also experimental but taken in a different (and very interesting) direction. unfortunately i couldnt find a crisp non-live version of this on youtube, but here is a concert link for anyone who might want to have a very rough idea at least.
june miller - neurosis
electronic beauty. one of those pieces that hit right to the heart (or brain rather), i cant imagine where id be without ever hearing that actually.
hm. i think i should really stop now.