NOTE: However the depreciated wrap="off" seems to be the only way for legacy browser support. Though it isn't HTML 5 compliant, it's still my preference if you're targeting all browsers.
If you have pre-formatted text that includes LFs, you should add white-space: pre; to the css. That will preserve the new lines that are already in the text and will not wrap long lines.
This works in all versions of Firefox, all Webkit-based browsers, and IE6+.