Tom at Disputations has decided to discuss the topic of universal salvation. His first installment, in which he lays out what he sees as the three possible views which might be held on this question, is here, although the link may not work until Tom makes another post (for whatever reason, links to the "top" post haven't been working -- if they ever did).
As Tom mentioned in the initial post on this, where he decided to discuss the issue, there seems to be a "Great Wheel of Catholic Debate." Tom explains, and shows the relevance of the wheel for Catholic blogdom: "The inescapability of the Great Wheel of Catholic Debate, the fact that every subject has its canonical discussion that repeats itself again and again through time, is what will eventually doom all blogs with functioning archives; they are destined to become like the comedians' club in the joke, where people tell jokes by number."
I think he's right, even on this issue. I believe that Tom was part of a brief discussion on universal salvation last year; for my part, I posted on the topic -- and my take -- here. Briefly, there is nothing which the Church teaches which requires Catholics to assert that there are definitely human beings in Hell. Furthermore, much of the Church's prayer -- including the liturgy -- includes prayer for the departed, with no limiting qualifications. In other words, we should pray for all those who have died. Now, if we knew that some souls were in Hell, then prayer for them would be purposeless, and it would be pointless to pray for all the deceased, as the Church does. Hence, we don't know if any human is in Hell, and we should pray that in fact no human being is there.
That's my take.