BioWare's been pretty good about DLC support. Not everyone can agree it was all worth paying for (Warden's Keep, anyone?), but the studio learns quickly. The adventure continues for both Dragon Age: Origins and Mass Effect 2 as 'Witch Hunt' and 'Lair of the Shadow Keeper' make their way to consoles and PC.
'Witch Hunt' brings us back to Morrigan, who's popped back into Ferelden almost a year after you (or Alistair) killed the Archdemon. Now is the time to confront her about that ever-so-creepy night of passion. We'll say no more, at risk of revealing too much more about the base game.
'Lair of the Shadow Broker' reunites Shepard and his/her crew with Liara. Her vendetta drives both Shepard and a former comrade into hunting the mysterious Shadow Broker, a faceless and dangerous entity who once tried to steal Shepard's corpse from Cerberus. Wonder how swanky the Liara's apartment is...
The Dragon Age DLC is the cheaper one, at $7 or 560 Microsoft Points. Liara's adventure will cost you 800 Points, or $10; if Overlord was any indication, this add-on should please everyone.