A galley kitchen would indicate that you would have cabinets on each side of the kitchen running the long way. A 10' wide kitchen with cabinets on each side would leave less than six feet to install an island. If the island is three feet deep you have less than 18" of space on each side which is not enough room to do any work. I think you may be talking about a peninsula at one end of the kitchen. If it runs 5' out from the wall the cabinet run on one side will need to be quite a bit shorter than the other side to allow for movement around the peninsula. Seating on the peninsula will be adequate for only two stools to avoid being cramped. A picture of the space will help clarify what we have to work with. Hope I have shed some light on the matter.

Great explanation from above. 10 feet is too narrow for an island unless there is only cabinetry on one side of the kitchen.

Yes, you are right, I was referring to a peninsula......do you think this will look ok given the long and narrow area? Ps family room is same width and another 20 ft longer....worried about a bowling alley effect. There will be no cabinets at the far end where peninsula is...just openings to hallway, family room etc.