@Nine It depends entirely on what the thing is doing!

If it's a big emergency-stop button I want something with a reliable clunk when pressed, and a big, easy-to-hit-in-a-panic button area, but one that takes a fair bit of force to actuate (so you can easily press it if you whack it like you'll probably do if there's an actual emergency, but hard to accidentally press).

If it's a keyboard, I like the kind they use in laptop keyboards; not too much travel, quiet, but reliable feedback.

If it's buttons on a device I'm making that don't have any special requirements, tactile switches because they're cheap and easy to use and provide good clicky feedback.

If it's on a piece of test equipment, radio buttons are nice for things that need radio button functionality (though it's impossible to get radio buttons anymore), otherwise slide switches and knobs of all types and maybe a keypad of either tactile switches or laptop-keyboard-style switches for things that you can't really do with the other controls.

If it's a power button for industrial machinery, I like the ones that don't take too much force but have a deep travel and are shrouded so that you have to push them with one finger and can't accidentally push them by leaning against the machine. Bonus points if you can hear the clunk of a big contactor after you press it.

-F