Well, MS is up first, so, let's put it this way, I'm gonna be sceptical and expect some fail from them, so if they can make announcements of actually decent first party exclusives (Not Halo btw), and NOT meet the following criteria:
*Multi-plat titles with BS exclusive dlc that costs $50 million to keep off the PS3, and inevitably FAIL to do so (I.E: Fallout 3 DLC)
*Stolen exclusives from the PS3 in order to screw the competition
*General shit exclusives which they need a dumbass pop star to help advertise (I.E: Lips)
... then I might change my opinion about MS. Last year's E3 failed to impress me, which is what sent me into my PS3/Wii favouritism, so if they can actually announce games that will help the industry grow, and show that they are capable of a more diverse range of first party games instead of relying entirely on the third parties, then I will see them in a better view from before.