What is, overall, safer for your body: alcohol or marijuana?

Do different kinds of alcohol (specifically liquor) actually make you different kinds of drunk? Or is it a cultural/psychological thing? I've noticed that I feel different when drinking wine vs. vodka vs. tequila, and I'm wondering if there's a physiological reason.

My 21st birthday is coming up. I've already had two sets of friends and my mom's boyfriend offer to take me to the bar for drinks. The problem is, I have never been drunk before, let alone consumed alcohol. I chose not to drink for a few different reasons and am not sure if I should change anything for my birthday. On the other hand, I feel that I am obliged to go out drinking on this "special occasion."

I am a healthy, fit, 18-year-old male. I have tried both ways: consuming small amounts of alcohol regularly (one standard drink a day) and consuming a lot of alcohol irregularly (10 to 20 standard drinks in one night, but only two days a month, or thereabouts).

I have tended towards drinking a lot irregularly because I have found that I can't notice any effects until I have had at least four or five drinks, 80 to 100 proof shots, usually mixed with soft drink.

I was wondering if either way was less healthy or more of a risk as the same amount of alcohol is ultimately consumed. Also, I noticed that I got a bit more of a 'beer gut' when I had one-a-day than 15 at once; is that likely or just my imagination?

Recently (the last six months or so) I've been getting really tired after a couple of drinks (let's say three or four). By eleven at night, I'm ready to call it quits. My friends and boyfriend poke fun at me because I usually head home before they do. How can I last longer in a healthy way? I definitely try to drink water throughout the night, but is there anything else?

What can I say to prevent someone from drunk driving?

Lately, my boyfriend has been sleepwalking. I'll wake up, and he will be sleeping elsewhere — downstairs on the couch, his roommate's room, etc. At first, we thought it was funny. However, now that it has reoccurred (more than once or twice), he is very upset about it. He thinks it is from drinking too much. Could this be the case?