I come from a part of the country where there is a constant market in old Martin and Gibson guitars. In general, these instruments are my first choice and where I would start looking if I were shopping.

The used instrument market requires that a buyer shop by the particular condition, and playing characteristics and sound of each instrument. That makes me want to say that to anybody who asks my advice on guitars. Even for new instruments, I really think you have to shop by the instrument, not by the brand.

Salesmen at music instrument shops aren't your friends in this process. Difference between instruments are sometimes subtle. It's pretty easy to influence a buyer unless they are really experienced.

If your money situation is comfortable, a new guitar from the high end Martin lines will give you an excellent instrument. If there are things that don't quite suit, Martin repair guys can usually set up the instrument to your preferences.

Taylor, Larrivee, Collings etc. are great if you don't really need the "Rolls Royce" cachet that a Martin brings when other people are looking at your guitar neck.

For the real thing, buy a pre-1970 Martin in decent condition. There is no better instrument that can be had (or bragging point-- short of actually playing well, of course).