Halo 3 is one hell of a shooter. An improved campaign and more balanced multiplayer make this game awesome.
The graphics in halo 3 are definetly not the best out or even the best on the 360 for the matter. However they are a bit better than they need to be, because halo was always more about fun, gameplay and to a certain extent story. So even though a game like gears of war has better graphics there isnt nearly as much going on in gears of war(such as explosions) as there is in halo 3. The gameplay is pretty solid. They didnt change everything in halo but they did change enough for it to feel like a fresh game.Having you start off with the assault rifle in multiplayer is brilliant, because that weapon is pretty capable of killing people with a better gun. The campaign in the gmae is very improved over its two predecessors, but it is still too short. On normal it'll take anywhere from 8-10 hours to beat by yourself. The music in the game really adds to the story of halo as well. The biggest improvement in the game is developing more characters than just the masterchief and arbiter. Something im pretty annoyed by however is that the arbiter doesnt play such a big role. He basically has a one scene at the beggining, in the middle and at the end.He basically just follows you and helps but there isnt much story for him, unfortunatly. Also i think the relationship between him and master chief could've been explored more. My final complaint with the campaign is the repetition in the last two levels and the warthog being unrealistically light. Overall the campaign is pretty good and conclusive.
The multiplayer is basically like halo 2 except with more balanced weapons.