Car - Love of cars is for life, but cars themselves only last a few years
Music - Taste fluctuates throughout your life - beware of anything dedicated to a particular artist or even genre
Raving - I used to hit the rock clubs every week or two, these days I take in the ocassional concert (rock clubs are a thing of the past), again, iuts rellevence to our lives comes and goes
Drug - The only people I know who did drugs for life died young, I know a handful who 'do the odd reefa' still, certainly drugs are a long way from defining them.
I would suggest going for something that either by it's own merit just represents a stage of your life that you would like to remember forever, or something that defines a part of who you are - some personality attribute or such (and ye gawds dont make it an emo one). In your case for instance, you could go for something that relates to your youthful hedonism.