Korg KDM2 Digital Metronome - (New)
I really like the sound this metronome makes.  It is loud enough to hear no matter how loud you play.  It also has a lot of nice features.  A choice of tones to contrast with whatever instrument you are playing, a nice large LED light that flashing the rhythm that is very easy to see, and such features as a nice tap in button.  The big problem with this is that they somehow seriously screwed up on the tempo control.  This is a large knob on the front that you should be easily able to spin around to set the 