In addition to seating 4 (or more), islands today are used to house "luxury" appliances that do not fit in the cabinet structure like a second microwave, second oven, wine refrigerator or even another cooktop. Islands many times are fully wired for electricity and have plumbing for a second sink. The base of an island can be used as a wine rack. The possibilities are almost endless.
If you are looking to do a complete kitchen remodeling for yourself, or for maximum resale value, don't neglect the kitchen island. Once just a place to pull up some stools so the kids could eat before running to the bus, the island and it's function in the kitchen has changed quite a bit in the last 10 years.
Safety First! You are better off without it if you are using up all the free space in the room. Your kitchen should be spacious and you should never feel restricted in your movement - in fact it can be dangerous if you are. Yes, a kitchen island is good to have, but not if your safety and freedom of movement are compromised to accommodate it.
The kitchen is perhaps the most visited part of any home. Here is where hearty meals are lovingly prepared and shared over pleasant conversation among family and friends. Here is where kids sneak off to eat ice cream in the middle of the night. Here is where couples end their rendezvous with microwave snacks just before dawn. Here is where cups of coffee are savored and papers are read every morning.