[youtube]http://www.youtube.com/watch?v=86QFWTQV__8[/youtube]
I think Voris is wrong in saying hoping all go to heaven isn't logical and is a vain hope.
What about the Fatima prayer? "Lead all souls to heaven, especially those in most need of Thy mercy?"
I believe Pope Pius IX answers your question in #17 from the Syllabus of Errors:
III. INDIFFERENTISM, LATITUDINARIANISM
15. Every man is free to embrace and profess that religion which, guided by the light of reason, he shall consider true. -- Allocution "Maxima quidem," June 9, 1862; Damnatio "Multiplices inter," June 10, 1851.
16. Man may, in the observance of any religion whatever, find the way of eternal salvation, and arrive at eternal salvation. -- Encyclical "Qui pluribus," Nov. 9, 1846.
17. Good hope at least is to be entertained of the eternal salvation of all those who are not at all in the true Church of Christ. -- Encyclical "Quanto conficiamur," Aug. 10, 1863, etc.
18. Protestantism is nothing more than another form of the same true Christian religion, in which form it is given to please God equally as in the Catholic Church. -- Encyclical "Noscitis," Dec. 8, 1849."
Since we cannot know the future, we can and should pray for the conversion of sinners.