The '70s were not Martin's best years. A great many of the guitars they put out in that decade had misplaced bridge saddles which created intonation problems. I had a '71 or so D-18 that seemed fine except it never developed much power in its tone, and I gave up and sold it.

A suggestion for a guitar that works for both flat- and fingerpicking, and sounds good in alternate tunings, is the Martin model formerly called D-18VMS, now just D-18VS. An "old-style" dreadnought (12 frets to the body, slotted headpiece, wider neck); the extra volume in the "shoulders" where they come up to the 12th fret gives it lots of extra ring and power. I have one that was my "best" guitar for years, and is kept in DADGAD since I got my Collings, it sounds even better in that tuning.

Martin's supposed list price for these is about 3 thousand US. That means a new one should run you about 2 from a reasonable dealer, and a good used one maybe 1,500.

Peter.