The end of the Halo Trilogy. This is what you've been waiting for. And it was worth it.

User Rating: 9.5 | Halo 3 X360
Concept:
You are a super soldier of the future. You are humanity's last hope to defeat the alien Covenant force now plaguing Earth. There is another threat, as well though. The Flood. A horrible parasite race that The Covenant are just as terrified of. Even the mystic Forerunners feared the Flood. But you're Spartan-117. Masterchief, John. Its your duty to stop this threat and save the Earth.
You get your answers in Halo 3's story. Finally.
Oh. And you get to play online co-op with three friends. Plus? I think so.

Graphics:
The graphics are such A STEP UP that I didn't recognize Sergeant Johnson in the beginning of the game. These are the kind of graphics we were waiting for. They are amazing. Every piece of environment stands out. And to show off this graphical improvement, you start in a jungle, aside form the usual Human Spacecraft. Enemies are more than what I hoped for. Grunts with methane tanks shooting out their contents, Brute armor chipping off with every bullet, every grenade explosion. These are next gen graphics.

Enemy AI / Difficulty:
The enemies don't just get stronger with every difficulty up. They DO get smarter. The Brutes have a pack mentality. They move together, attack together, and retreat together. The Grunts will stick by their sides defending them at times. Add this all up with Legendary, and you'll have a hard time getting through alone. Its well worth the challenge.

Gameplay:
The controls are different from Halo 2. Reloading and picking up weapons are different. There are a few new tweaks to the controls. For Halo 2 players, its a hard adjustment, but very managable. Nothing bad. Except the couple dozen times you're gonna try to reload and throw out your Bubble Shield instead. Everything is smooth, though. The frame rate is good.

Multiplayer:
Possibly the best aspect Halo is known for; multiplayer. New weapons, MANY new maps, new armors for your Spartan, so many things to dive into. There is a mode for everyone, I tell you. There really is. The one drawback to Halo 3 multiplayer...you will be met with loud-mouthed 12 year-olds. It happens on almost every game these days, but I warn you...Halo 3 is bad for this. Get past that though, and you should have a great experience.

Replay Value: Very High -
You can collect all the skulls in Campaign mode, beat campaign on Legendary with friends, get all the Free For All achievements in multiplayer. Then theres multiplayer itself! This can hold you over.

I know this review is late in the game, but I hope it helps new players decide on what they want.
Thank you ~