You'd think that Protestants and Catholics would agree on soli Deo gloria. Well, perhaps they do in theory, but the papacy has a tendency to elevate men above their fallen, mortal status.
Then there's sola scriptura. The Catholic Church continues to believe that the Bible can only be correctly interpreted through Holy Apostolic Tradition by the Magisterium. It also teaches that church tradition is on par with what is revealed in God's Word.
Sola fide? Instead of Faith = Justification + Good Works, the Catholic formula remains Faith + Good Works = Justification.
Sola Gratia conflicts with the Catholic teaching of merit, so there probably won't be a consensus on that anytime soon.
But can't we even agree on solo Christo? Not quite. Pope Benedict XVI invited people to pray to God "that he will awaken in all of us this desire, this openness to God, and that those who do not know God may also be touched by his love, so that all of us journey together toward the definitive City and that the light of this City might also shine in our time and in our world."
If that's all that's needed for salvation, what was the purpose of Christ's sacrifice?