The KJV was the standard English version for most protestants since the 17th century and is still used often. However, since the majority of protestants contested the 'apocraphal' books (those not in the Hebrew canon), they were first moved to the end of the Old Testament, then eliminated by the 20th century. Additionally, you're dealing with 17th century Middle English and some words are now obsolete or have actually changed meaning. For instance, Middle English used the word damsel (actually stolen from Old French) to properly translate the direct old Hebrew equivelent, na'arah; modern translations use the less defining word, girl.
As
Tacit indicates, the New Testament was a collection of letters/documents written in old Greek (
had to edit: I would have made Fozzer happy -- I left the "r" out ;D ): the life and times of Christ and his followers. The version of the Old Testament in Greek (written a few centuries before Christ) was the Septuagint (supposedly written in 70 days; septuaginta is Latin for 70).
The more common Modern English Catholic version in the U.S. is probably the New American Standard Bible which contains the additional Catholic books (Apocraphal per protestants). My basic theological studies were Catholic based but I used the New Jerusalem Bible for my reference. The basic Catholic version is the Latin Vulgate and, if I'd gone Catholic all the way, I would have had to learn Latin, the language of the Romans, but that would also have taken several more years and I was afraid if I Romed to far I'd get lost.
More recently, I've usually been using my Thompson Chain New International Version (NIV). However, my arsenal -- ah, bookshelf -- contains:
King James Version
New Jerusalem Bible
Good News Bible
American Standard
I also have the New Testament Parallel Bible (KJV, Living Bible
[a paraphrased version], Revised Standard Version
[1800s but there's a newer, late 1900s version], New English Bible, Phillips Modern English and New Jerusalem). Then I have a Parallel Greek and English New Testament. If you're serious about knowing what was translated from what and can't find a Hebrew-speaking rabbi, a Strong's Exhaustive Concordance will also be useful.
It also seems that the Koran (Quran) is being confused with Qumran, the place where the (possibly Essene) Dead Sea Scrolls were found. However, the Koran is the bible of the Moslems, the followers of the prophet Muhammed; something quite well different.
P.S.
Ozzy, a few million of the Orthodox may be taking potshots at your Spitfire for that errant, "seeing as how Catholicism is the original Christian faith," statement.
...hmmm... Are you guys talking about Pete's first templates then? ;) 
