Check out Professor Longhair. "Rock 'n Roll Gumbo" is my favorite. Some consider him the missing link between classic American jazz and modern rock and roll. Elvis was heavily influenced by him.
http://www.professorlonghair.com/index.html
A local favorite of mine is Cuban jazz pianist Nachito Herrera
http://www.nachito.net/
Amazing stuff
For someone coming from a classical background, try Jean Luc Ponty, jazz violinist. My favroite disc of his is "Individual Choice".