Another excellent one is Let the Right One In (opt for the original Swedish version). It depicts how a vampire might actually operate in the world and it has the truly great 'I'm twelve...I've been twelve for a very long time' moment.
The thing (original with Kurt Russel) is an absolute classic.1982 but don't let that put you off
Also event horizon is pure genius. 1997
And dog soldiers is the best British horror of all time. 2002
Alien is and always will be a true timeless classic along with the excorsist
I'm not big fan of horror movies but "The Conjuring" is best movie i have ever seen. You must watch this.