Well, I think that more recently MS has been focusing on Kinect TBH. My feeling is that for the existing core they'll look to some further sequels (Gears 3 and the like) as well as securing a couple of exclusives from third parties (like Kingdoms) however, unless they are working on a lot of stuff they're keeping quiet I do think that in 2011 there may be less core exclusives than before.
To compenstate for this I do think MS will continue to invest in exclusive or timed exclusive DLC - such as with CoD.
It makes sense in that the existing base is secure and will remain with 360 for third party titles, of which there will be plenty. MS probably don't see as much advantage right now in exclusives for the core vs focusing on Kinect and breaking into the more casual market.
I suspect if things do start to look weak for the core they'll quickly look to fund some further timed exclusives (even if just to annoy me as I hate timed exclusives on any platform!).
At this point though I think MS options are more limited. Few third party developers want to be exclusive anymore and many third party titles sell between 40 to 50% on PS3, so just being on 360 doesn't look that great (nor being just on PS3).
Try to be reasonable... its easier than you think...
