Congratulations, Laura - and to everyone else who's managed to quit the bad stuff. 
Fortunately, one of the few good things my parents did with raising me was to give me a strong distrust of drugs and tobacco and alcohol. My parents almost never drank, smoked or took anything (though my dad did used to smoke and occasionally drink beer when I was a little boy - an amusing story about *that* in a moment), so fortunately they were good "role models" for me in that regard.
When I was about 4 or 5 years old, my maternal grandpa was a major chain-smoker. One day he was in his bedroom taking a cig when I came in and asked what he was doing - I was just very innocently curious. So he held the cig for me and let me have a taste. It was SO nasty that I'm proud to say I've never touched any tobacco ever since!
Okay, a drinking story. As my parents told me, supposedly when I was about 18 months old, Mom and I were in the kitchen, Mom was working on something and I was seated at the table. My dad and grandpa came in from the garage to take a break, opened a couple of cans of beer, then had a sudden idea and went back to the garage. Mom stepped out of the kitchen briefly for some reason... and a few minutes later, one of them came back and found me sitting on the floor, a can of beer in my hand, burping and quite happy. 
My drinking history has been very, very timid since. In my grade-school days, I'd sometimes come home from school, and my dad would be sitting in the driveway in a neighbor farmer's truck, both drinking Coors and yakking away. I'd come sit with them for a while, and they'd let me have sips of their beers. I thought it tasted strange but pretty good. Fortunately they never let me have more than an occasional sip.
By my high school years, I saw a lot of my small-town schoolmates always going to parties to get wasted. Being the rather introverted lone-wolf that I am, I never wasted my time with it. I honestly didn't and still do not understand how getting super-dizzy, nauseous and puking up one's own guts, and basically losing all self-control is supposed to be "fun." I think my own *lack* of control over my own life under the rule of my tyrannical dad quite possibly gave me a sense of desiring to *take* any self-control I could find - including a decision to not party and get drunk. It wasn't an act of rebellion against "teenage peer-pressure," it wasn't *just* because my parents told me getting drunk was bad... it's what *I* wanted for myself.
In my adult years (I'm 32 now), the number of beers in a year can probably be counted on one or possibly two hands, usually just having a beer with a good dinner when out with friends.
Hard drugs like cocaine or ecstacy or heroin I've never had *any* interest in taking, period.
"Light" stuff like pot I used to distrust, though I'll confess in recent years I became curious, and twice tried smoking pot with a friend of mine who smokes it regularly. Honestly... other than giving me a coughing fit and feeling only *slightly* dizzy... it didn't do a thing for me. No "high," no nothing. Two times, not gonna bother with it again.
I *am* curious about other natural drugs like psychedelic mushrooms. Years ago I'd toyed with the idea of seeking some kind of "enlightmenment" through their use, but I've found enough enlightment through my own natural, unaltered senses and thoughts to fill that bill. However, I am curious to have a psychedelic *experience*, though I'm not actively seeking it. If the opportunity falls in my lap, I'll give it a try. 
- Burke aka "ChaoCatcher"
"It's my estimation that every man ever had a statue made of him was one kind of sommbitch or another." - Captain Malcolm Reynolds in the FIREFLY episode "Jaynestown"