There are two powers I'd really like to see. One because it's just cool, and the other because it lends itself to a great antagonist:
The first is shapeshifting. Genuine shapeshifting. As in, his body can go all gooey and take on any shape he likes. Like the bad guy from Terminator 2. Best way they could explain it is by saying that his entire body is in fact a hive mind of single celled organisms. In essence, it would make whoever had this power the least human of all the Heroes, which might lend itself to some interesting character stuff. Plus, the versitility of the power could mean some very good fight sequences.
The second is the ability to later reality itself. Obviously quite powerful. However, as it would most likely also be quite complex, the Hero in question would most likely be limited by his or her ability to focus and comprahend certain concepts. In any event, I could imagine this ability having a great tole on someone's sanity. Especially if they add in something like the nature of the ability is that the Hero in question is able to see and is aware of the countless millions of quantum possibilities, picking and choosing which ones are real for him, and even exerting his will over them to alter reality for everyone else, making him something similar to the theoretical "Ultimate Observer." Might be interesting if he starts off on a loony bin before he realizes that he has powers and isn't just deeply schizophrenic. I also thought it could be cool if the Hero starts using his powers to give his fellow inmates a set of fairly eccentric super powers, and becoming a group akin to DC's "Brotherhood of Dada."
