In the final director's cut there are tons of clues that he is a replicant, but it is still debatable. In the end it doesn't matter because the point is to question what is defined as human. If a man-made robot can think, has memories, emotions, and believes it is human then who is to say they are not.
So while I am eagerly awaiting the pc release of max payne 3, I was googling some news about the pc version and came across this. Rockstar posted HEALTH's version of the Max Payne theme. Here's the link. It is awesome and free!