Red, pignut, and mockernut are my favorites in this area, roughly in that order. There are some local ones I haven't tried, like the bitternut, sand hickory, or shagbark (shagbark is really rare here in the mountains.) Any of them should make a bow, though. If I remember correctly, the two fastest bows in the infamous "whitewood wars" bow tests at Mojam were Tim Baker's pecan bows.