My belief is that KJV is indeed COMPLETELY correct translation AND almost every other translations out there, which may not be outright or wholly wrong, DO CONTAIN a few verses in all of them which perverts the word of God to something clearly incorrect.
Now, can anybody be saved reading other translations? Sure, as long as they do not use the corrupted verses. Does that mean this translations are completely correct? No. Is KJV completely correct? Yes.
Do this thing. Make a list of all or major bible translations out there and go to their Wikipedia entry. Most will have a NT and OT source entry. Read and note that down. You'll notice that most of the bibles are translated from "Nestle-Aland Greek New Testament" or "Westcott and Hort 1881 and Tregelles 1857" or "Novum Testamentum Graece". All these family of manuscripts are called minority text and contain two major blasphemous manuscript called Codex Vaticanus and Codex Sinaiticus. Moreover the origin of these manuscripts are found to be from 4th century AD Alexandria, Egypt. Whereas if you look at KJV, NKJV and Geneva Bible, it has taken its NT from Textus Receptus which is taken from a group of manuscripts called the Majority Text which have their origin in 1st century AD and the text style is Byzantine. They are called Majority Text because there are over 5000 of them. You can read more about these things at below link and decide which line of manuscripts you will follow.
http://www.tbsbibles.org/articles/what-todays-christian-needs-to-know-about-the-greek-new-testament
Unfortunately although NKJV traces its origin to Textus Receptus, it still contains blasphemous verses as it was influenced by other modern versions. You can learn more about these things at the following link.
http://av1611.com/kjbp/faq.html
Also look at this pages for a list of these verses
http://www.av1611.org/niv.html
http://www.av1611.org/nkjv.html
http://www.av1611.org/kjv/ESV_Fruit.html
So, there. As long as you avoid these verses you are OK. But are you going to bear the extra mental burden to look out for these kind of verses when you read your bible or are you going to have peace of mind reading a KJV bible?
As for the question of other languages, would you choose a bible of questionable heritage or would you choose one known to be correct? Well if you want to read bible in other languages, it's fine. Just keep your KJV ready for doublecheck.
EDIT: When you look at these changed verses you will find that many of them are cosmetic changes which do not interfere with the central doctrine of Christianity at all, but they are changes nonetheless.