Wow, tough call. There's no one favorite for me. Here's a short list of who I enjoy listening to and may have influenced me in some way:
Alain Caron, James Jamerson, Duck Dunn, Jimmy Haslip, Jaco, Rocco Prestia, the Nashville session cats, James Brown's various bass players, Todd Johnson (my teacher), Steve Kim (another teacher), John Patittuci, etc...