That question may be unanswerable as stated.
Most any answer you get is going to be highly subjective, methinks. And I suspect you're looking for versatility, rather than power.
When I was using VB, it
was the most versatile.
Then when I used Turbo Pascal or Delphi, they were, in turn, the most versatile.
As far as raw power, C/C++ will likely take the lead, but there will be differences of opinion even there.
Power/versatility, other than really hard core programming, are mostly going to depend upon what you are trying to do at the moment. Each language has degrees of weakness and strength, and each has differing ways of dealing with GUIs.
I'd suggest that you pick a language, then really learn it. That's the only way you're going to discover whether it will perform according to your needs
. If it doesn't try another one (1). Sooner or later, you'll find the one (1) that truly suits your needs and purposes. Yes, it's an arduous process, but the only one (1) that works in the long run, at least in my experience. There really aren't any shortcuts