Silvertone Dark Star.
The reason I'm suggesting that one, even though it is a basic cheap guitar, is because I once listened to a youtube comparison of acoustics where the guy played five acoustics, didn't show them and asked people to vote in the comments on the best sounding ones, in order. A week later he posted the results. The guitars were: A custom made one which was over twenty grand, a Martin, a Taylor, a Tanglewood and the lowly Silvertone. Many people placed either the Martin or the Taylor at number one, but then put the Silvertone in seconds place, a few people, including me, put the Silvertone at number one. When the results were revealed, I immediately went to get one of them, which I found at Chase in Manchester and paid less than a ton for it. It had an horrendous picture of Paul Stanley and the Kiss logo on the front, so I oversprayed that to make it completely gloss black, sorted out the nut, the bridge and the frets, swapped out the tuners for some much better ones, put a soundhole pick up on it and an Aspri spring reverb unit. It's now my main acoustic gigging guitar and whenever other guitar players hear it, they want to have a go with it and usually end up wanting one.
My theory is that because it is cheaply made, the top and bouts are wafer thin, and that makes it reverberate really well. I have lots of other, theoretically 'better' acoustics all of which cost more than that Silvertone, including an Epiphone AJ, Aria MBA, Fender MA-1, Harmony Sovereign and a Gibson MA41, but that Silvertone blows them all out of the water for sound.