I hear a lot about the superiority of the King James version, but I'm not sure why.
I am told by my father that the best one to get if in particular you're interesting in knowing what the blazes Ye Olde School Fundamentalists are on about, especially for understanding Calvinist politics and its influence on the US, the best one to get is a variant of the Geneva Bible (or a Tyndale, of which 80% is in the Geneva).
if you want to know the "general christian" viewpoint, the KJV is where it's at.
As he tells it, the KJV is a pro-monarchy interpretation used to justify the doctrine of the Divine Right of Kings and the justness of interceding authorities between an individual man and God, whereas the Geneva Bible is republican (no-King-but-Jesus type) and stresses the direct relationship of the individual man to God. I don't know how much truth there is to that.