Unless you simply must have Metal Gear Solid or Final Fantasy 13 there is no reason to buy a PS3. With every day that passes with PS3 sales lagging the possibility that it will ever even catch 360 - let alone pass it - grows smaller. That's because the incentive for developers to tackle the incredibly difficult programing decreases in turn. With PS3 losing ground every day this is unlikely to ever change.
Here is an interesting take from a former Harmonix programer who basically blasts PS3, essentially saying that the technological advantages are exaggerated and that the 360 is in many ways superior as a pure gaming system.
Former Harmonix developer shoots down PS3 tech in rant - PS3 Fanboy
And one last thing D, don't listen to anything Quake says about gaming. He has admitted in past threads to being a PS3 fanboy unable to think objectively about the topic.