Don,
Looks great! Love all the pics and the details.
My vote is for the island. My reasoning is it adds one more point of interest to your place. It could easily be planted in flowering shrubs that wouldn need any maintenace since nobody goes they, the shrubs could just take over. It is also a safe haven for waterfowl. Migrating ducks, resident ducks, or if you get the urge, buy a few pet ducks, geese or swans. My goal is to have a few Ruens (sp) swimming around in my pond. Too many and you have a poop issue, but three would be just about right for me. And the final reason to keep it is the kids will love boating around it. I have a small 10 ft plastic boat that I take the kids boating in. We go around the island a few times and they have a blast.
Either way, it's gonna be quite the showpiece!!!
Eddie