pickups
Just another data point/opinion: I've kept Baggs Dual Sources (with the ribbon UST) on three of my guitars (including my D-40) for a dozen years. The mike and soundhole-mounted volume/blend unit give good control over sound (though I don't play at feedback-inducing volumes). Other instruments have a B-Band soundboard transducer and a Highlander coax UST (both with their matched pre-amps), and they both sound quite good, though I miss the volume control that the Baggs offer.
The problems with choosing a pickup are that 1) it's a real pain to try most of them out, 2) it's a matter of matching the technology to the particular guitar, and 3) results often depend on the installation as much as the electronics. For example, one of my guitars came with a Highlander that the previous owner liked. I hated it and replaced it with a Baggs Dual Source. My Goodall also came with a Highlander, but it sounds fine. Most of the pickup systems that will be recommended will sound terrific on some guitars--but on not all of them. And installation can be very fussy--I'm told that Highlanders, for example, are quite sensitive to how they're seated, and B-Band installs seem to require lots of messing around with location. The most you can do is listen to lots of setups and be prepared to have your tech spend some time on the installation process.
