Originally downloaded April 21, 2007. Yeah, me too. I haven't found anything that doesn't just become annoying eventually, however, for general typing. I use the terrific (and free) MooSB preference pane for other system sounds. BackTrack, a key logging app I use, can also generate typing noises, but again it wasn't flexible enough. Keyclick sounds like it might be just the thing. At $2.50, it's practically free (though its price will double after May 15, 2007). I'll certainly be trying it out.
Keyclick now costs $7.99, so it's more expensive than before... but it does do what it promises. And it's kind of fun fiddling with the output options. If you need some audio feedback when typing, scrolling, clicking the mouse, etc., this is what you're looking for. The software has been updated to 64-bit, so it loads into System Preferences without a relaunch. The only problem I had was that it requires a logout in order to take effect, but Keyclick didn't tell me that.
Version as tested: 1.0.6.
Update 8/17/12.
