What are the things you liked about Halo 3

I want to see what you veterans have to say on this along with you casual folks as well. I am currently building up a post and not only that, making a constructive paper for my class about Halo in general. So please fill me in on your thoughts on what Halo 3 so great.

I was thinking of making a thread like this maybe a day or two ago…
What I like about halo 3 huh?
-The fact that you could play as an elite or spartan in ALL game modes in matchmaking
-No armor abilities
-Good maps
-fun weapons to use
-felt like Halo.

Reach has shown me how frustrating armor ability noobs are, but Halo 3 has helped me appreciate Reach’s better graphics and the new maps.