So you have narrowed down your search for a banjo by figuring out you want a:
Now you need to figure out what neck wood you want on your banjo. The two most popular are mahogany or maple.
Maple is a very hard and dense wood. This wood when used on the neck of your banjo will give the instrument a very bright tone. This is generally the preferred neck wood/tone for traditional bluegrass banjoists. This is most likely due to the fact that Earl Scruggs, the king of bluegrass banjo, played a maple banjo and had a very bright tone.
Mahogany is a much less dense wood than maple. When used as the neck wood on your banjo it will give the instrument a much warmer tone than maple. Some feel it is a sweeter tone. Bela Fleck plays a mahogany banjo and gets a very warm tone from his banjo. J.D. Crowe also played a mahogany banjo and was able to get a more bluesy tone.