First, it should be perfectly clear that Holy Mother Church in no uncertain terms condemned a certain brand of Universalism. (Mr. Sullivan disagrees with me on this, and I acknowledge that, but respectfully disagree with his interpretation of the anathemas.) The type condemned is that which say that at the end of time God will be reconciled even with the fallen Angels and all shall be restored to his good graces. There is a Greek word for this that I have to look up every time I refer to it and the thought has been attributed to Origen, although perhaps incorrectly.
The Church, wisely, is silent on the question of the disposition of any given soul, and although theologians speculate, the Church remains silent on the question of whether or not all people will be saved. There is certainly a good deal of scriptural evidence that can be argued either way on this point.
However, one reason that I am Catholic is that this door remains ajar. Admittedly, it takes a person of strong constitution to deny that there are people who are capable of saying no to God out of sheer cussedness. I believe this is possible, but I do not believe that it is common. Moreover, I do not hold with those who say that a great many shall be condemned. I know that the visionaries of Fatima seemed to see this, but Fatima, being private revelation is not binding on anyone except, perhaps, the visionaries themselves.
The Catholic Church is agnostic on the question of who is saved and who is not, even while remaining adamant that Hell exists and contains at least the fallen angels, and that unfortunate part of humanity that rejects God's mercy and salvation.
Here are some points that I often reflect on. I have no answers, because I can argue back and forth using scripture, theology, logic, common sense, intuition and any number of other even less effective means. Is God's arm too short, or His grace too weak to save those He wills to save? And who does He will to save--only the remnant, the smallest portion of humanity? If the latter, what sort of God is He, who claims to be love, and yet out of hand condemns the majority of His creation to an eternity of punishment? What is the meaning of love, if we can say in one breath God is love, and in the next, but the majority of humanity is damned? What must a person do to be saved if God is so busy keeping track of all of our sins to send us on the express freight to Hell? And what does this say of the image of God as father?
I will suggest answers to none of these, because there is a perfectly legitimate series of counter questions that could be asked: If God is simple and purely Holy, how can He abide what is unholy? How does perfect justice allow the unrepentant sinner to come to the same end as those who lived lives of forbearance and service to others? The list goes on, but I don't ponder that list nearly as much, and there are better people to ask and answer those questions. I point them out merely to indicate that the question is not so cut and dried as I would like it to be.