I have the tap-to-click feature enabled on my Magic Trackpad and find that it works very well for the most pat. However, I think it tends to be a little too sensitive at times. Is there any secret adjustment for reducing the tapping sensitivity of the Magic Trackpad? I assume that the same setting will also apply to the built-in trackpad on MacBooks.
Unfortunately the sensitivity of the tap-to-click feature on the trackpad may not be adjusted through the default system software at present. It may only be turned off altogether.
However if you download BetterTouchTool it will allow you to adjust tap sensitivity, among other things.
Not a complete answer Use BetterTouchTool. Under the Advanced Trackpad->Taps setting is an option to adjust the time and pressure sensitivity for three and four finger taps