Consider that Metal Gear Solid 4 has a fantastic chance of coming out on the 360, and there is also a chance that Final Fantasy 13 will be released on the 360 in 2009, the same year as the PS3. So your top 'PS3-exclusives' have questionable exclusivity.
So far, everything that was supposed to be big for the PS3 in 2007 was either delayed or fell far short of expectations. It makes sense that, if the delayed games actually come out in 2008, it will have a pretty big year if they don't keep falling short of expectations.
Nintendo's style is often to leave big games unannounced until they're closer to release. It's basically the opposite of Sony, who seem interested in playing up all of their games as huge AAA games and suggesting they'll come out much earlier than ever possible.
Just because we're not aware of huge games coming out for Nintendo in 2008 aside from Mario Kart, No More Heroes, Wii Fit, Animal Crossing, Final Fantasy: Crystal Chronicals, and Wii Music doesn't mean there won't be many more huge games. Hell, in the beginning of 2007 we had no idea SSB:B and SMG would be released in 2007 (although we suspected Metroid Prime).
