Most Important Instruments of a Drum Kit

Personally I like the sound of a bass drum more than snare drum. But snare drum is important. You need to beat the snare every-time. Otherwise it won't make a rhythmic beats

I like it, especially double bass drum which is widely used in metal (I am a big metal fan).

Crash is important. Its more needed when you are finishing a note. And also for the powerful guitar riffs.