I don't like the Alien being susceptible to bullets. Something about the idea just doesn't feel right. It's such a beautiful monster creation and its weakness is gunfire? Lame.
Ridley Scott intended to make something that we don't understand. Being able to kill it makes the Alien less... well,... alien. I applaud James Cameron for trying to go a different direction, and I think the Alien Queen looks cool, buuuut, I'm not a big fan of Aliens. In fact, I think I like Alien 3 better (though I see the movie's flaws). Aliens just dumbed down the Alien too much for me to like. It was so interesting and original and BAM it's shot with a pistol a couple times and it's dead.