Well I think the Newt scene is creepy, but not scary as its pretty obvious that's she's going to be grabbed. But the scenes when Riply is going Into the nest invoke feelings of fuck yeah! Go kill those things. By the time we've gotten to that scene I've seen the Aliens many times and I've seen them killed many times. They have lost their luster, I know their tricks. In Alien not only do you have the holy shit scene where you realize that it's still with Riply in her escape pod, but also when it kills Dallas. Those scenes are way more effective. Dallas, because you know shits about to go down , but not when, where, or how. It's the feeling of waiting that gets me. Also for the escape pod there's a sense of false peace, you know it's like "wait the movie is still going, oh god it's not over and then hey what's that?". I don't get many scenes that invoke something like that in Aliens, but then again I watched them when I was already a teenager and well I wouldn't expect them to scare me that much.
But yes the first encounter is pretty scary especially when the camera just shows them crawling.
Somewhere in Japan, Sakamoto is watching this trailer with a grin on his face. 
