According to this, the second Mass Effect game will build on the enormity of the original, especially in the side quest department.
"Side quests can sometimes be left on the side, so to speak," said Bioware's Greg Zeschuk. "Pardon the pun. But a lot of times it’s even just getting that whole game done, that first shot [that is important]. We look at Mass Effect 2 as incredibly exciting. Just the amount of effort and knowledge and know-how that went into building the technology for the first one is huge, and [we now have] the chance to actually make things a little bit richer."
No word on when the sequel will be released, or for what platform.