This might be a different and interesting topic, i understand that Colin and Greg read this forum and just entered post, so it might be inspiring for them also.
PREDATOR SOUNDS: Personally i like the sound of the predator the best from Predator 2, when its pissed of at Danny Glover in the meat factory and it starts roaring and breathing heavily. I think the sequel has a nice variation of sounds, i love the clicking sound and the roar but the good thing in Predator 2 is that it has a good variation of sounds and still it sounds like an alien and not like recorded animals, but i guess it was recorded animals and people but mixed respeeded and reverbed.
I love the scene in Predator 2 when the pred is hanging of the roof, after it said Shit Happens and activates the selfdestruct device and it breaths heavily. Would be nice if the Avp 2 predator had some of those sounds.
ALIEN SOUNDS: Aliens and Alien 3 has the best alien sounds, in the first Alien i remember it only screams and some hissing. Aliens has a great variation of hissing sounds that i like. The queen also sounds awesome in Aliens, the creature sounds are really creepy and still fits the action film that the second movie is.
AVP SOUNDS: The Avp movie lacked variation, it sounded like the predator only had like 2 sounds restored from the first movie and then revocalized in different speeds and variations to make it sound like its doing different vocals. But it only still sounds like 2 sounds it had had the clicking and the roar. The Aliens sounded too much like a monster.
Something new and something borrowed from Aliens and Predator 2 would be cool for AVP 2. The first sequels from both franchises have the best sounds!
/Ola