Peak? I'm sure MS will continue pumping out exclusive games (and hype them to create crazy interest).
I do wonder how big a seller Halo Wars will really be though -- dunno if it will really approach Halo-level sales.
I think the Playstation 3 is still too expensive to the average person (who groups the Wii, 360 and Sony together as "just" game systems), and the video format war is pretty much a nonissue because of consumer apathy (compared to DVD).
If the $400 system starts taking too big a chunk out of the 360's sales, expect a more effective price cut this year from MS.
Seems clear to me that Sony will pass MS in Europe, stay over them in Japan, and forever be third banana in the U.S, probably for the rest of the gen.