Well, Watch Dogs, Killzone, Drive Club and the Witness have all been confirmed as launch titles and I'm a pretty big fan of the first three developers. I'll probably buy the system if I have disposable income at the time, but Killzone is very close to must-buy territory. I usually burn a lot of hours in Killzone multiplayer and their offerings so far have been pretty substantial. Battlefield and CoD are in that territory as well.

But as far as MUST must haves, that would be Valkyria Chronicles, Metal Gear, or Final Fantasy. FF only if they show us something more than the last console FF's have been.

I also have to say Uncharted is very realistic as a launch title, since this Q4 is around the time they would normally be releasing one.