I asked for and received one of these Couch guitar straps last year: http://www.couchguitarstraps.com/ . I got one made out of the trunk lining material used in old Mustangs. Could always get him an assortment of picks, too. Just go to a music store and get a bunch. Mechanical metronomes are good, too, if he doesn't already have one. I've had a Taktell Super-mini for a long time.

There are a few books he may like, too, like histories of certain guitars such as the Telecaster. There's also amp books like this: http://www.amazon.com/Amped-Illustrated-History-Gr... .

There are mini amps available, too, They are battery powered types that look like Orange, Fender and Marshall amps. Although if he doesn't have a Roland Micro Cube, they are really handy to have around and are awesome little amps: http://elderly.com/new_instruments/items/RMC.htm

You may want to look here to see if any collectible type things look good: http://www.musiciansfriend.com/collectibles

Tim and Renee are right.

Also think about some sheet music for guitar. Pick something in his fave genre, ask your Mom if 1960's unplugged is good, or if he likes rock or pop.

Scan the web for collectibles in your price range.

Go to a vinyl record store [thee are two in out city] take your Mom and pick out something jazzy, or

blues.

Pick a CD that he does not have.

music note clock, DIY Guitar Pick Punch, vintage Musical Note Bookend

Maybe a new guitar strap, guitar stand, or a tablet holder that attaches to the mic, so he can use his tablet as a digital music sheet.

Go to www.GuitarTrinkets.com for some really unique guitar related gifts. They'll treasure things like these forever.