I've never sailed on Navigator but from the descriptions of Portofino's, it would be a once-a-cruise experince for me.
Joanna, I like the idea of a seafood night. Or, "billp1's"(sorry I dont' know your name), suggestion of a changing menu.
Welcome, Steve. Love your avatar. Now, if only you could put a picture of yourself inside the porthole - that would really be cool!