Good fun, but just another shooter in a world filled with them.
Graphics are fantastic just like in any Halo game to date. They may not match to Call of Duty, but they still look amazing. Sound and everything help the game's case, and further enhance the way it feels to play Halo.
However, gameplay is nearly the same after all this time. It follows the template of a first person shooter, which is important. But the game relies too much on that template that the game doesn't have much to show against the competition. Vehicles are one of the few unique things of the game, and although it's fun at first, it gets old quick.
Gun selection is also good. My personal favorite is my choice for the best of them, the needler. The gun selection puts the game above Army of Two and Left 4 Dead 2's variety , but still falls short to Call of Duty.
All in all, Halo 3 is a good game. It's fun to play, but it has been greatly overhyped. This game is good, but there are many other games better than this. Maybe they'll add something new to Halo Reach, but only time will tell...