Bioware producer Casey Hudson, speaking to Videogamer, has revealed that the current line of DLC being produced for Mass Effect 2 will eventually bridge the gap between that game and its sequel.
"So, for the time being there's going to be a continued stream of DLC for people. We'll start to have packs that'll tell the story between Mass Effect 2 and 3. But beyond that we kind of have to see how people are responding to what we have and go from there."
Interesting angle, I think. But it does kind of mean that the best time to play Mass Effect 2 is... when the sequel comes out? The next major piece of DLC is due in June. It's called Overlord, and sees the Space-Chums Funtime Gang battle an evil AI in five levels set across a single planet.