I'm sorry, but people who are voting Angle astound me. The man is a smark's dream I realize, but he's an average at best wrestler at this point in his career.
John Cena wipes the floor with any of these candidates this year. The only one who comes close would be HBK, but that's in part because of his matches with Cena. Cena had the TWO match of the year possibilities in Umaga at RR and HBK on Raw, not to mention a very good WM main-event, a very good match with Bobby Lashley, he carried Orton to a solid main-event at Summerslam, and made not one, but TWO matches with Khali interesting and entertaining. Cena is my obvious choice.
Out of these candidates, it goes to Shawn Michaels. Even with the injury, HBK has had good bouts before and after.
Edge is not that good of a wrestler. He's overrated because he's a good gimmick match wrestler and can talk. His in-ring skills, in classic bouts, are average at best. Undertaker only comes around every once in a while, and was injured for part of the year as well, so I just couldn't vote for him (at least HBK is a full-time wrestler). And AJ Styles has been in tag team and specialty bouts for most of the year, and really hasn't been given much of a chance for good and solid singles bouts.
All of these men (including Cena) have very good charisma and presence, so it's just really their in-ring work being evaluated.
Cena was easily the best, but out of these choices, I'm going with HBK.