I have a theory that most people who are arguing in favor of pot in this thread aren't old enough to know what it means to be responsible about such things. Statements like that support my theory. When young, your tastes are different than when you are older. You like sweets, you don't like onions or garlic -- or wine or beer. So when an 18 or 20 year old drinks, they can't even fathom the idea that you might drink for another reason than getting drunk. The stuff tastes terrible, so who would drink it because they like the taste?
Drinking for the sole purpose of getting drunk ends nearly completely by the time a person reaches 25 or 30 and then you either drink almost nothing or you drink different things because you like the taste. I have a bottle of Vodka, Jack, and Tequila that have been sitting on my counter for 2 years and are still 3/4 full. I don't really like them, but some of my friends do, so I bought them for a party. I also have a half a case of Coors Light in my fridge that that I bought for a the same party. I drink wine and good beer, and that's about it. Yeah, if I'm out at a bar (I have a good one very near my houses), I'll sometimes drink more than a couple, but the last time I was drunk was New Years' and I can't remember the last time I vomited. Responsible people still drink scotch or Jack a vodka tonic. It's different from the way you drink in college, where you look for the easist hard alcohol to drink when mixed with a little fruit juice, so you can get drunk the fastest. A buddy of mine likes a glass of Johnnie Walker black with a cigar, but I think that's only because he aspires to be a lawyer...
Whether with alcohol or with drugs, it is self destructive. In particular, kids do it in college because they can and it gets in the way of academic achievement. I have a number of friends with similar stories: they spent the first two years drunk and high and getting bad grades (one failed out), then got their act together, reduced their drinking and smoking, and got better grades in their junior and senior years.
I haven't really stated my position fully in this thread. I used to be completely against pot, but only in about the same way I'm against cigarettes. I don't have a very strong opinion against doing it, say, once a week for entertainment and in the same way, drinking a lot once a week for entertainment isn't too bad either. But that isn't the way the drug/drinking culture works for kids in their late teens and early 20s. Drinking and smoking pot dominates their lives.