Hard work is great, but nothing without talent. Talent without hard work, is a person with little to no work with talent.
Luck, is an accumulation of many things, and doesn't exist as a stand alone element in the world. Luck is made, but it's rare that people see all the little things that comprise luck.
Ultimately, I would have to choose hard work and talent. I couldn't pick one over the other. As, success simply doesn't exist without both. Success is an end result of taking action, being persistent, and playing to your strengths. To choose just one, is like removing a piece of a math formula hoping to get the same result - it doesn't work.
And luck, well exists regardless of my choices. For worse or better.