[Modernman]

I'm such a stick-in-the mud that I believe it is proper and respectful to use "thee" and "thine" and "thou" when addressing God in prayer.

There's nothing more proper or respectful about using those words as opposed to their modern counterparts. Those are just archaic versions of modern words.

[Choose Ye This Day]

They are more formal, less colloquial. If anything, they help me remember to whom I am speaking, which I find helpful.