John - The advice Russ gives is one of the most important pieces you are likely to get. If you want to play an instument, but are not interested in the music or style that it suits, you are unlikely to persevere with learning it.
Decide what type of music you would like to play, then ask about what instrument would be best for playing it on!
If you want good advice about banjoes and musical styles have a chat with myself (5-string banjo) and Bill Sables (Tenor banjo AND 5-string in different styles to the ones I use). We can certainly tell you a lot about banjoes and other instruments between the two of us.
See you at the Jug!
Geoff!