I love all the new elements brought in by Portal 2, but I have to say the single element that made me shout out loud with amazement when I grasped the implications was the hard light bridges. Wow. I'm on my third playthrough now, I keep finishing the game and thinking "Man, I want to play with those bridges again. I'll start over."
Light bridges are basically instant humor devices in coop. I need to play through again, this time with a few beers, and I'm sure I'm going to kill my partner about a million times on accident.
I am not sure why everyone likes the Aerial Faith plates so much; I admit they are useful on occasion for making puzzles, but the other aspects more interesting, IMO.
I think the later test chamber where Wheatley tells you to tell him before you complete it, and then gets mad when you don't that uses the faith plate, uses them really well as a puzzle element and not a means of transportation.
I'm quite surprised how people don't seem to like the energy pellet much. I've been thinking of one puzzle that would involve using light bridges as angled pieces to ricochet an energy pellet around correctly. I hear the energy pellet has no texture in Portal 2, I wonder if we can get this working? Also I wonder if the light bridges would deflect an energy pellet or not.
Hard Light Bridges combine best with other elements.
They go mad with the High Energy Pellets and edgeless savety cubes.
gotta make a map where you paint an edgeless savety cube in blue gel and have it hit an energy pellet while bounching.
The energy pellet actually adds some force on the sphere and reflects on collision.
The funnel, because the transitioning between two funnels is cool, with the gel transporting also being very cool. Just putting anything in the funnel is fun.
It's not listed by the turretcubes are hands down my favorite.