Close to 3.5 million. Maybe 4.5 million, if the ps3 drops to $299 and either GT5 or FFXIII make it out this year. GT5 is far more likely to hit this year than FFXIII, but I'm not getting my hopes up for either.
I think that both consoles will sell roughly the same in NA, with the ps3's big exclusives offsetting the 360's popularity.
In the EU, I think that the ps3 will outsell the 360 by at least 2 million. MGS is by far the most popular in the EU, so that should really boost sales, and if GT5 makes it out this year, then it could outsell the 360 by as much as 3 million in this territory alone.
In Japan, the 360 will be more dead than ever, since it's three big JRPGs (Blue Dragon, Eternal Sonata, and Lost Odyssey) have already hit, so it won't receive any significant sales spikes this year (Cry On won't be out until '09 at the earliest). This combined with plenty of big hits for the ps3 (White Knight Story and MGS4 should really spike sales) will cause the ps3 to outsell the 360 by at least 1.5 million, and probably much more if GT5 makes it out by Christmas.
And then there are the wildcards of Killzone 2 and LittleBigPlanet. Will LBP catch on like the Sims and spur casual adoption? Will Killzone 2 actually turn out AAA? If Killzone does end up being a great game, then Sony could turn into a Gears of War-type system seller with the right marketing. Of course, the chances of that happening are rather slim. ^^







