Most important things for me are:
Story (There has to be a start, a middle and an end)
Melodies (unless it has really wicked sounds it has to have a melody)
Sound (The more intricate or original the track/song is the more I like it)
The "it" factor (Very few producers have "it". There's a lot of good music I like but only 10% of it has something special. Something like Shpongle, Hallucinogen, Pink Floyd etc.. Something beyond the 3 other criterias)