Outside of the Ent scenes all of those are quite integral, holy shit!
Some of those weren't outright cut. The only Ent scene I can think being cut was Merry and Pippin drinking the entmoot (the water that made them grow). Alot of the Merry and Pippin orc stuff is just heavily trimmed down, but still present in the theatrical versions.
Also the previous poster was incorrect, the first we see of Eomer in the theatrical version is him arriving at Edoras with the King's son. His exile ends with Wormtongue saying "..under pain of death," but the exchange about the King making it official is cut.
The stuff about Aragorn being as old as he is was cut. The funeral for the King's son Theodrid is cut, so when the King asks where his son is, it cuts right to the shot of the grave. The Boromir flashback was cut (which sucks because it's one of my favorite scenes). Some of Faramir's lines were cut, as was his threat to Gollum at the end.
As far as Fellowship goes, I think alot of the cuts were alot more justified. I like all the extended stuff, but there is some worldbuilding stuff that feels more unnecessary, and there are some more natural transitions.
Fun facts though... the shot of Aragorn kicking the Orc helmet and screaming? They did that acouple dozen times, but the shot that made it into the movie was the last one because on that kick, Viggo Mortensen broke his toes, and gave out a WAAYYY bigger scream than any of the prior takes.
Also during filming, Arwen joins the elves fighting at Helm's Deep. There are shots of her side-by-side with Aragorn fighting all these Uruk Hai. Obviously that and a whole subplot where she visits Galadriel in Lothlorien were cut.