And while we're on the subject, could someone please sum up the difference between Catholics and Christians in about 1 or 2 lines? I've never really understood.

From the FAQ:

"...Evangelicals hold that the Catholic Church has gone beyond Scripture, adding teachings and practices that detract from or compromise the Gospel of God’s saving grace in Christ. Catholics, in turn, hold that such teaching and practices are grounded in Scripture and belong to the fullness of God’s revelation. Their rejection, Catholics say, results in a truncated and reduced understanding of the Christian reality."

Interesting side-by-side comparison chart on that page, too. Shows you how much I know... I was baptized and communinized as a Catholic, and went to Catholic elementary school for two years, yet I don't know the difference between the Immaculate Conception and the Virgin Birth of Jesus. I'm not sure if I never knew the difference, or just confused the concepts at some point.