You smoke weed, it chills you out and brings a smile to your face. You smoke too much and you just have a nice sleep, after a quick bout of the munchies. You never feel emotional or angry, just at complete peace with everything. Some people feel paranoid, I never have. The next day, you feel just fantastic, like you had a perfect nights sleep.
You drink alcohol, and you get a nice buzz. Drink more and you get shit faced and probably become an asshole. Drink more again and you lose all sense of personal boundaries, or become just plain antagonistic. After that, it's all puking and passing out. And then you probably have to get into a car. The following day (or more), you feel like absolute shit. It's good for a laugh though if you're with buddies or at a show. I never drink at home.
I don't really do much of either anymore to be honest, but if weed was legal, I would almost certainly smoke a big fat joint on a saturday night, or just take a couple of hits from the bong, listen to some Sleep or Yob, and then just fall into a really good deep, deep sleep.