This is a great question, and my friend Jodie Mesler has a great post about why she loves the pennywhistle here on her blog:
http://homemusicmaking.blogspot.com/2008/07/what-is-pennywhistle.html
Hope that helps some of you who are trying to decide over the summer which instrument to use or switch to!
I am very busy this week getting ready for the workshop Donna Simmons of Christopherus is doing this week for our regional area. She flies in today, and many of us are excited to hear this conference. You can see http://peachcobblers.blogspot.com for further details if you are interested.
Be back soon,
Carrie