What qualities do the best UX professionals have?

The ability to quickly see to the actual problem, not just the issues that result from that problem.
The ability to visualize that problem.
The ability to generate multiple solutions to the problem, then discuss the pros and cons of each.
The ability to sell the solution(s) via storytelling, visualization, and metaphor.
The ability to define, document, and prototype design details.
The ability to work with those who make the product (developers, printers, manufacturers, etc.)