Perphaps the OP is unaware of the Japanese and European markets where the PS3 has already sold more units then the 360 console (in both markets). in Japan FF13 was the biggest system seller and it seems that several games have been important for the console in the region. its been the best selling home console in Japan for the last few weeks and for most weeks of last year.
in Europe, the PS3 has also been the best selling home console for the last few weeks and for a lot of last year. thanks in part to Uncharted 2, but most importantly Gran Turismo 5, which has sold more copies than Halo 3 in Europe, despite only being on retail for 2 months.
there are several key games including MGS4 that were important. but in different regions, there have been several key titles. the only place where the PS3 is not doing comparatively well is the US.
