Hyped but unproven new franchises like Mass Effect and Shadow Run aren't going to be more than minor hits. They may well do over 1 million units eventually, but they won't sell to a lot of new owners, and they don't have the appeal of a Gears of War. Forza 1 only did 1 million units on XBox.
The summer is Nintendo's. The 360's summer lineup are merely the types of games which kept sales steady for the XBox brand for the last 5 years, but nothing which will put it past Wii in any region.
Edit: Eh, we are in the "gaming" section, not "sales." I don't want to argue the "quality" of unreleased games, though.
"[Our former customers] are unable to find software which they WANT to play."
"The way to solve this problem lies in how to communicate what kind of games [they CAN play]."
Satoru Iwata, Nintendo President. Only slightly paraphrased.
Essay Pro