The thing most fans should be excited for, is the synchronization between the scariness of Alien and the scope of Prometheus. Not just that it'll be scary. It's one thing to have one or the other, but when you get something massive and frightening, that's a gift and it should be celebrated. It's a gift that only the likes of Ridley Scott could bring to us. Even when Guillermo Del Toro had the backing of Tom Cruise and James Cameron, he couldn't get At the Mountains of Madness off the ground.
Scary? Check.
Epic scope? Check.
Cerebral? Check, per Ridley Scott.
All three of these elements working in congruity. Wow. Strap in, folks.