@shams : you have to consider that 2007 could not have been a more terrible year for the ps3, so much things were wrong :
#price : at $200 more than the nearest competitor, there is big trouble
#online : at launch, many functionnalities have been missing. It's so much better now, but still need a handful of key feature that may by delivered S1 08
#games : terrible bombing with Lair. Lukewarm reception of motorstorm (comparing to its true potential of course) due to lack of content. Heavenly sword not praised due to game length. Only ratchet & Uncharted managed to drive up the ps3 lineup. Terrible ports too. Madden, Orange box, etc. many games got delayed
#constant stream of exclusive losses : DMC4, assassin's creed, Fatal Inertia, Bladestorm, and a few others.
# competition : 360 had excellent games and better pricing with lead start
# PR : many PR fiasco.
# Bad press: relentless bad press in many major site and doom and gloom stories all over the net.
Those are what i think would push ps3 a lot :
# another price cut : $400 is still a lot of money and is not "instant purchase" friendly. a $50 price cut or better $100 would make it so much more attractive (the initial price of ps2 by the way!)
#slim model : it's quite sexy on photo, but when you see it it's big. a slim model woudl make it so much sexier and also less expensive to produce
#hammer an "impossible to do on 360" game to quite the doubters. UNcharted began, but not in the most familiar genre in US right now, the FPS. Either Resistance 2 or KillZone 2, but Sony better check before unveiling that it can deal a knockout punch.
# colors : what about a red ferrari ps3 bundled with GT5 ?
# ads : spare no expenses, momentum is crucial.
# New controller method with eyetoy : what about those video recognition ?
# Develop the casual market / educational games : you can't leave the door wide open for Nintendo.
If they follow those, i guess ps3 will sell a lot.
So if only after a year, with all those problems, it managed to go up to 360 sales on a ww level, then it has to at least sell 1,5x in 08, otherwise i have high doubts ps3 will ever pick up (by picking up i mean in a ps2 way).