There are so many good ideas to wade through here. My two cents: get a guitar that has a balanced tone from treble to bass. I like Martin 00's for this but early Gibsons and an occasional Washburn would do the job. Style has a lot to do with it. Many National Cone guitars give you the early blues feel that you hear by early blues players.
The best thing you can do is to locate the players whose sound you like and find out what they use. They will all be different and ultimately you'll have to create your own sound. Rosewood looks pretty but in a recording studio, they have a lot of overtones to compensate for.

If you're into Atkins, the Tenneseean or the acoustic/electric jobs might be something.

Classical guitars are not especially good for blues or ragtime.

I would avoid pickups, though. Don't mutilate your guitar. You know they never sound as good as the natural sound of a guitar or with a sensitive condensor mic.

One of the best natural sounds with fingerstyle that I have heard is Josh White who used to have an old Gibson that was stolen and then went to Martin 0021's (12 frets, wider neck). I like the wider neck for finger style because you can get a freer attack in between the spaced strings.