I can't think of many where it's really been done and done well. I like to personally end the big-bad myself, though. Buttons feel so indirect. The best example of "push button to beat" boss I can think of that did it well was in Resident Evil : Code Veronica, when you had to use a cargo delivery system to knock a Tyrant out of the back of a plane... But even there you had to use ammunition to weaken it down, and had to wait for the thing to charge. It was intense. Resources weren't all that plentiful. At the very least the player should feel like they're being given something special to do the job with. (Super Metroid, Doom, Duke Nukem 3D, Dead Space, Resident Evil 2 are all examples of doing that kind of thing well... etc.)
I mean, when the showdown comes, it better be an Earth shattering experience. If it doesn't get my blood flowing, ... If you can casually beat the main boss. That's a sign of failure. Especially when it amounts to push button, push button, oh buh-bye your highness.
