I loved it too. I give it 9.6/10, it loses a few points for that final boss battle and the occasional confusingness of the story. Also, some of the textures could have been improved.
I, being an evil bastard, harvested all but three Little Sisters, so as to maximise ADAM while still getting the Hypnotise Big Daddy plasmid.
The bad ending was pretty confusing, but I hear the good ending is a lot better.
I saw that trailer, it's up on the UK PSN, you can go download it. I've watched it like five times, it looks amazing.
I want to get the challenge rooms as well, but for now I am playing through again on hard to get some more trophies and get the good ending.
EDIT: Some things that could have improved it:
-Improving some of those textures. Even after the patch, some are subpar.
-While you are in a bathysphere, how about seeing outside on your journey instead of seeing a hints screen?
-That entire final boss battle. He was easier to kill than a Big Daddy, I swear.
-Being able to look into a mirror during the protect the Little Sister segment.
-Having less info in the diaries, and more in-game.
-MOAR PLASMIDZ!
-Letting you explore more of Rapture
-Being able to collect ADAM from dead bodies. Even if it was 1/10 bodies and it was 10 ADAM.
Some things that were awesome:
-The plasmids
-Atlas
-Big Daddies
-ADAM
-The story
-The fact that you actually need to think, as opposed to running and gunning.
-The different behaviours of the enemies.
I think it deserved Game of the Year 2007. I played CoD4, and it was very good, but derivative and standard. Can't judge Mario Galaxy, I haven't played it, but I can't see many games being better than this.
(Former) Lead Moderator and (Eternal) VGC Detective 
