I don't play guitar (just piano, like all nerds), but I think that the Pick Punch makes a great gift for that hard-to-buy-for musician friend.
The Pick Punch looks and functions like a regular hole punch, except that it cuts guitar picks from plastic instead of annoying confetti from paper--and it's more durable. It works with expired credit cards, gift cards, lids, and anything else of the appropriate width, thickness, firmness, and weight. The result is a smooth, traditional-style pick that can be used with any pluckable instrument.
The Pick Punch is practical, unique, and costs only $25. If you're worried that there won't be enough old plastic lying around, which is a reasonable concern, the Pick Punch guys also sell black nylon sheets for $3 that produce 56 to 85 punches.
An even better idea would be to use the Pick Punch on an old driver's license or student ID, ensuring that your musician friend is never without ample inspiration in the form of your laminated, awkwardly smiling face.
I did some punching around with the Pick Punch using one of the 50 used Starbucks cards I had lying around. You can check out my artistry in the video above.