K&K Pure Western Mini. Passive (no battery to faff around with, no extra weight), nothing under the saddle (it's an under-soundboard transducer, not an under-saddle transducer), no piezo 'quack'. Pure and 'natural' sound - the nearest to a real 'acoustic' sound I've heard.

The only drawback is that, like the Baggs, it's slightly more prone to feedback at high volumes than an under-sddle transducer, but that can be EQ'd out usually.