Warcraft 3 by Blizzard Entertainment

Warcraft 3 is a Blizzard title and third in the Warcraft series. This time around the Orcs and Humans face a similar threat in a group known only as the Scourge. The Scourge apparently are the follows of the Litch King and hope to free him from his prison. My favorite unit in this game is the Dryad and my favorite hero is the Dark Ranger (which appears as a playable character in the Frozen Throne Expansion).

Here is what Wikipedia has to say on the game:

One of the main new features Warcraft III offers over the previous games in the series is the addition of several powerful units called Heroes. Heroes can find or trade items to increase skills, defense, and other abilities, and with each kill of an enemy, the heroes gain experience points, eventually resulting in increasing their level and gaining new spell options (thus introducing RPG elements to the series). Certain heroes also can apply beneficial auras to allied units. The highest level that can be gained in a normal game is level ten. At level six, the hero can obtain an "ultimate" skill that is potentially more powerful than the others.

Another new feature is the addition of creeps, which are computer controlled units the player fights even in multiplayer. They guard key areas or neutral buildings and are designed to act as a resource for the players to kill to provide experience points to a player's hero and to provide hero items. The idea is to force the player to be aggressive instead of "turtling up" (spending all resources on defenses, rather than attacking). In The Frozen Throne Expansion Pack, Heroes can reach a maximum of level five from killing creeps; after that they can only get experience from enemy units/towers, while the highest level allowed is ten.

Warcraft III includes four playable races: the Humans and the Orcs, who also appeared in Warcraft and Warcraft II, along with two new races, the Night Elves and the Undead. During early stages of development, it was announced that Warcraft III would include six races, three of them being Human, Orc, and Undead. As an April Fool's joke before the game was released, Blizzard announced that the Pandaren would be the fourth race. The company didn't reveal the Night Elves until a month later, and pandas are now a running gag in Warcraft (to the point that a Pandaren Hero — called the Brewmaster — was available in the expansion pack, Warcraft III: The Frozen Throne). A fifth playable race, the Burning Legion, was changed during play-testing to a set of non-player characters and monsters (with a playable "cameo" on the last level of the Undead campaign, as Kel'Thuzad summons Archimonde), and a sixth playable race was removed during testing before announcement of what race it was to be.

Warcraft III has a large online gaming community centered around Blizzard Entertainment's Battle.net servers (called Gateways): Azeroth (U.S. East), Lordaeron (U.S. West), Northrend (Europe), and Kalimdor (Asia). Players meet other players to chat and set up multiplayer games through Battle.net. In addition to custom games, in which players have complete control over game settings (including map, teams, handicaps, etc.), Battle.net features a ranking system for certain standard game types: 1v1, or solo; various team games (2v2, 3v3, 4v4); and free-for-all (FFA). Ranked game play is facilitated by Blizzard Entertainment's Automatic MatchMaker, which pits players of comparable skill against each other. Players can also form clans comprised of ten or more players, which are also ranked. Unfortunately, the matchmaker does not always put up the teams fairly, sometimes, there may be a level twenty player and a level five player versus two level 5 players.

Warcraft III also includes a very thorough scenario editor. It uses a scripting language similar to the trigger system used in StarCraft. As well as providing the ability to edit any aspect of the units, buildings and spells, it has advanced features as custom tilesets, custom cinematic scenes, dialog boxes, variables, and weather effects. Many custom maps, featuring a large variety of game-types continue to be developed, and together with the expansion pack have contributed to the longevity of the game.