You've got the obligatory tin case, the 48-page Art of Mass Effect 2 in hardcover, the first issue of Mass Effect Redemption (comic book), and a making-of DVD.
There'll also be some in-game perks not available through other means but details are sparse as to what they might be. Those of you looking for other in-game exclusives should look into pre-ordering as you can benefit from additional armor.
The CE version will retail for $69.99 on the Xbox 360 and $59.99 on the PC, which is about a tenner more than the standard edition price. Worth it if you'd class yourself as a diehard fan. Let the countdown to January 26 begin!