Hello
Roger - well, there are so many choices, so offering a specific recommendation may or may not serve your needs?
For myself, I have two small traveling speakers: 1) an older set by Altec Lansing (below left) - folds for easy packing & works on batteries and/or an adapter; 2) Brookstone speakers w/ iPod adapter (that's how I carry my music on the road) - use rechargeable batteries but will work w/ the included adapter.
NOW, there are so many other options that you simply need to decide on your own needs, the price you are willing to pay, the power sources, and the storage space desired - good luck on your choice(s) -