Also, I've been thinking of some kind of big company or cooperation that specializes in suppression of powers/ technology/ magic, etc, etc.  Basically, these guys will be able to alter reality in various ways, depending on what their costumers want.  Maybe some places don't want anyone to have any access to magic and other places just don't want anyone with technology to be a bother.  So they'll call these guys, and they'll come and set up fields which'll nullify said problem, or post agents equipped with various weapons which can easily by pass special abilities and items.  

The reason why i'm leaning towards this idea is because it allows for a much greater range of characters and abilities since there's always going to be a universal constant which can put a stop to them.