Alatar:
Good points about the orcs and fire. Now that I think about it, fire in the movie can associated with burning down, torching, destroying, blowing up.... and all those 'qualities' go along with 'orcs'.
Yet there is one instance in which fire can be associated with "protection". Namely, when Aragorn fights the Nazghul off. He uses fire to hurt them, and in the books we hear that they don't really like fire.
Maybe "fire" in the movie is not necessarily an orc thing, but rather a fighting device.
Also, about the different kinds of orcs, I see what you mean... but in the movie we don't have any clues about a third group of orcs, so maybe it's just a pale mordorian orc with a very nasal voice? Yet your guess is as good as mine... but I'm willing to give PJ a break on this one.
Essex
I hope it does not sound as if I am trying to find reasons not to enjoy the movie... to be honest, I could watch it time and time again and I still won't get tired. I have probably seen Theoden's "speech" before they charge to break the siege in Minas Tirith a couple dozen times as that scene still makes me shiver.
I agree that the scene with Eomer, the Rohirrim and the hunters is masterfully done. I think the acting is good and the ring of spears is at least plausible
... and with regards to Eomer's going from foe to friend quite easily, while it's "technically wrong" I can see why it was needed to do.
On the other hand, I don't think that Merry talking about the Old Forest is an 'anticlimax' of sorts. I think that it both gives hints about the upcoming Ents (and so, it makes the talking, walking and not very hasty tree less of a shock and more of a surprise*) and it's one of the points in which those of us who have read the books realize what they were talking about and what would soon come up.
*: What I mean by 'less of a shock and more of a surprise' is that it's less of a "why in the Lord's name is that tree walking?" reaction and more of a "wow, that's amazing!" reaction