Final answer:
A portable electronic device connected to speakers, such as a smartphone or tablet, would be the best storage device for Jon, the traveling DJ, to easily transport his large music collection.
Step-by-step explanation:
The best storage device for Jon, a traveling DJ who needs to easily transport his large music collection, would be a portable electronic device connected to speakers. This can include a smartphone, tablet, or portable music player. These devices are lightweight, compact, and can store a large number of music files. Jon can simply connect the portable device to speakers to enjoy his music collection wherever he goes.