rod selection for average saltwater fishing

[flyred06]

If you had the choice for only one rod to do most all saltwater flyfishing what weight rod would that be? I have a 10 weight now also an 11 wt but I am wondering what size rod do I need to complete my tackle selection for smaller species like bones, permit, striper, reds and so forth. Any info will be appreciated. I don't want a rod that over powers the fish so they are no fun but isn't to light as to over play the fish causing them harm.

Thanks