First and foremost, there is no best. Period. What might be best for me could be far, far, far from what might sound best to you. There is classic, however, and if ever there was a classic Martin sound, it is that D-18, pure flattop acoustic goodness. I've played more than a few, and when you find one that is right, well, boy howdy, that's it. That's it, that's it, that's it, no bones about it. That is a classic Martin sound and feel. J,M & J, the first time you feel that feel, and hear those angels, well, then you know. And you don't really need anyone else's opinion really. Oh sure, Martin makes plenty other good stuff, great stuff, really and it's a wonderful world. That being said, I've played a ****ton of other acoustics, mostly USA style, including the Gibson, your Taylors, Boudreau, Santa Cruz, Collings, plenty boutique, as well as a lot of the Canadian & Asian varieties, Larrivee, Yamaha, Takamine, Hondo, lots of stuff that people swear by. And that's wonderful too. My adventure led me to a Gibson Advanced Jumbo. That was it for me. Sure, I've got a friend whose got a D-16 and one of those little New Yorker Martins that is amazing, both of which I would love to play at any time, but for me, it's my AJ. At least so far. But now I'm curious - what you gonna do with all these opinions?