Guitars for beginners

A reader has emailed and wants to know what kind of guitar to buy her 10-year-old boy. He wants to learn to play guitar, but she's clueless. (No comments there, please.)

Ergo, the question: What kind of guitar would be good enough to give a good start, but not so good that it would be a waste of money if the boy decides he ISN'T destined to be the next Randy Rhoads?

The only musical instrument I've ever had custody of was a loaner alto sax in band and a loaner French horn. We have a guitar or two in our house, but ....