I just picked up the orange box so the new games for me out of the orange box are: Team Fortress 2, Portal, and Episode 2. I logged something like 60+ hours in the first 2 weeks on team fortress 2 and haven't even touched episode 2 or portal. Although I am burned out on team fortress 2 (for the time being) and moving on to some different games.
Just picked up Space Rangers 2 for $4 so looking forward to trying it out.
Lego Star Wars II: played the hell out of this over Thanksgiving. Fun game.
Played Dawn of War: Soulstorm intensely for about a week and a half. Beat it with a couple races and am ready to put it down. A fun game, I love DoW games, but this game seems a bit lackluster compared to DoW: Dark Crusade.
Guild Wars Trilogy: I recently picked this up as well. 3 guildwars games for $50. So far I have only played 3 days, but I am digging the hell out of it. I will probably go over to this full time as soon as Hellgate London and Tabula Rasa die or I tire of them (again).