I side with the ps3 optimist point of view. The ps3 was on the upswing for the entire beginning of the year, and MGS4 only furthered that along, all despite being far more expensive than the 360 in all regions.
A price cut later (two in Europe), and the 360 was back on top for a short while, but the ps3 is already back to outselling it in Europe, and should be back on top in Japan this coming week. Microsoft has used price cuts to spur sales in these two regions about as much as they can by this point. The price is so low now that further cuts will do little if anything to boost sales. All they have left now is North America (though they'll receive a small spike in Japan from Star Ocean 4).
Compare this to the ps3, which is still rather expensive in all regions, and thus has plenty of room to spur sales via price cuts. Not to mention, the releases of Gran Turismo 5 and Final Fantasy XIII should provide reasonable spikes for the console, in Europe and Japan respectively.
By the end of this year, the ps3 should be back to outselling the 360 worldwide, thanks to Europe and Japan (though White Knight Chronicles will be necessary to keep the system afloat in Japan), and starting with it's next price cut, the gap in sales between the two consoles should become pretty substantial.
I'd say the ps3 surpassing the 360 by the end of 2009 isn't out of the question, especially if both GT5 and FFXIII hit before then (FFXIII in Japan, obviously).







