A complete Masterpiece that Bungie can proudly call their finale!
Let's start with campaign, while the previous Halo games required you to play the campaigns in specific order (if you wanted to have the faintest idea of "what the hecks goin' on?") Halo: Reach has a stand- alone story which players can enjoy with or without previous knowledge of the series (Although the campaign is so good that it may inspire gamers to pick up/ replay the series.)
While the campaign provides between 5-15 hours of game play (depending on difficulty setting.), the multiplayer portion(s) of the game add endless game play hours (reducing that small fragment of a "social life" to crumbs.) Halo: Reach offers a near perfect matchmaking system which balances game play effortlessly and nearly instantaneously. While I could write infinitely about the multiplayer I'll just say that it alone is enough to warrant a purchase of H:R.
Above and beyond its outstanding campaign and multiplayer, Reach offers high levels of customization, including: Forge (map editor), Theater (watch replays, take photos and capture videos), and Game Type editor (which allows you to tweak everything from spawn time to weapons on the map.)
The Forge mechanic of the game has been completely overhauled creating an experience unlike any other! In Halo 3, Bungie boasted a map editor that was easily accessible, but with H:R Bungie has created an editor which basically creates maps by itself!
With so many completely different features, I would contend it to be impossible for anyone to not find at least one feature of the game that they love and completely blows them away!
10/10 -A Masterpiece (and game with the biggest heart)!