The Martin D-45 is the guitar that every acoustic player wants... the true holy grail from the Caddy of acoustic guitar builders. It sells new for about $7,000, so it's not for the faint of heart, but it's well worth the coin if you know that it's the one for you. It features a spruce top, Indian rosewood back, and sides, beautiful abalone accents and inlays, Waverly tuners, a rosewood bridge and the typical dreadnought body style. It's built in the USA and is the top of the line production Martin instrument made... definitely the real deal here.
The design of this guitar is pretty simple. It's the classic dreadnought, but adorned with the best woods, the best craftsmanship and some beautiful features. The dreadnought body might be a bit big for some players, but it's worth it to get that big booming tone. The neck is a nice comfortable profile that is like a cross between a C and a soft V and it definitely feels amazing. The finish isn't super glossy either, which is great for playing fast up and down the neck. It's a fairly light guitar too which is awesome. The upper fret access is not great, but it's not too bad considering that it's a non cutaway acoustic. Getting a good sound is very easy... you just strum it and the sound comes alive. It's a very rich guitar in all frequencies, and it is perfect for a variety of acoustic styles for the truly discerning players.
The sounds out of this guitar are basically the holy grail of acoustic tones. It has a very rich and clear low end, strong and authoritative mids, and slinky, piano like highs that all blend together to create an acoustic tone that works well for many styles. I tend to like this one best for really dynamic rhythm chord work (especially up higher on the guitar) as well as for bluegrass style flatpicking, because every note is clear and not dead sounding, perfect when you're playing a mile a minute. It's also good for basic chords in the lower register, as well as for more dynamic slower lead work as well, whatever you want, it's there and sounding awesome.
All in all I think the Martin D-45 is truly a sight to behold. Sure, it's VERY expensive but it's well worth it for the tonal quality. It's got beautiful craftsmanship and looks, the classic Martin feel, and a very full sound that any serious player would love. I'm fortunate to have a relative who owns one of these so I do get a chance to play one and really get to know it and I'm sure that if I had to have the best acoustic in the world, I would go for the gold and get the Martin D-45!