The Brood war expansion pack is fantastic. You've only been playing half the game if your playing Starcraft without it. The story line continues from the original Starcraft with extra missions and new troop types. Unlike other game expansion packs Brood War actually feels like it should be part of the original rather than just being bolted onto it. If you love being Terran then buy Brood war just for the Medic, which heals (repairs) Marines and other troops. Medics are best used in pairs (so they can heal each other) Few opponents can stand up under the onslaught of two medics and a full group of marines, together they will do a lot of damage. If you love Protos buy Brood war for the Dark Templars who are not only permanently cloaked but can meld with another (Like Templars) to create Dark Archons who in turn have the MIND CONTROL ability to steal units from your opponent. Unfortunately if you're a Zerg player (like myself ;0), the Zerg don't do as well on the new troops. The Devourer is a new Air to Air attack flyer. It's a little expensive in both minerals and time (evolves from a Mutalisk) compared to its damage. The Lurker, which evolves from a Hydralisk is the only unit that can attack whilst burrowed. Since no unit can move while it is burrowed the Lurker becomes just a glorified sunken colony.  It's well worth buying this expansion pack