The thing which annoyed me about the N900's bzzt (and the screen clicks on any other Maemo device) is that they always go off when you touch the screen, whether you've touched an element which does something or not.

So, as a feedback indicator it's useless: it tells me my touch had been registered. Fine, but the N900's screen is so sensitive, I don't have any concerns it wouldn't be. What I'm interested in is has my touch been picked up as doing what I wanted to do.