An extension method to get the current user
When I encountered a similar issue I had a base controller that the rest of my controllers inherited from. Then, on that base controller there was a read only property named User that got the current user. 

Personally I think inheritance can be confusing when it is abused just like everything else. As long as you keep your base controller relatively lean, and don't use it as a place to drop random methods which may not used in every controller, then I think inheriting from a base controller would be a pretty straight forward solution.