Hi joarc, it's really hard to say. Do you want to do the Panama Canal or do you want to do islands? I haven't done the Panama Canal itinerary, yet, but do have it on my bucket list. I have been to Aruba and Grand Cayman. They're both flat island, clean, decent shopping, decent snorkeling. I have done the southern Caribbean and really, really enjoy that itinerary. St. Thomas is a popular stop, very busy island, scenic, good beaches, decent snorkeling. We usually go over to Trunk Bay from there, which is fantastic. St. Kitts is a beautiful island, not overly populated or Americanized. Aruba is a flat island, so not much scenery, but nice beaches and very clean. Curacao is a great island, very colorful, good snorkeling, good shopping, very scenic.
Without knowing what your intersts are, it's hard to say.