I loved the original Dawn of War and Winter Assault, even though Dark Crusade and Soulstorm ruined the first series I was adamant to give Dawn of War 2 a go.
The Campaign is one of the most best I've ever played, because instead of focusing on building a base and then spamming the most powerful unit, you only have 4 squads to control. This ruined the game for most “Die Hard” RTS players yet it made this game immediately my favorite RTS game.
The Campaign also has the ability to play it online with a friend in CO-OP mode, which makes it even more fun IMHO.
Dawn of War 2 Gold pack includes the GOTY edition and it's first expansion: Chaos Rising. Chaos Rising continues the story of the Aurelian Sub-Sector about a year after the events of Dawn of War 2, and allows you to choose your ending, out of Uncorrupted, slightly Corrupted, mainly Corrupted or completely Corrupted. What the ending is depends on the options you take in game, each mission after the 3rd allow you the chance to corrupt or redeem your squads, also the war-gear you equip them with can also either corrupt or redeem them.
The Last Stand is my favorite game mode. In The Last Stand you choose one from: Eldar Farseer, Space Marine Captain, Ork Mekboy, Tyranid Hive Tyrant or a Chaos Sorcerer. In game you face off against 20 waves of enemies with two other players.
The one thing this game has that is lacking IMO is the multi-player skirmish.